Winch-Assisted-Harvesting-Best-Practice-Guide.pdf

New Zealand Winch-Assisted Harvesting Best Practice Guide 2 Steep Slope Harvesting Best Practice Guide Foreword The New Zealand forestry industry has seen a huge shift from manual to mechanised harvesting in the past few years, greatl...

New Zealand Winch-Assisted Harvesting Best Practice Guide 2 Steep Slope Harvesting Best Practice Guide Foreword The New Zealand forestry industry has seen a huge shift from manual to mechanised harvesting in the past few years, greatly reducing risks to manual fallers and breakers-out. However, mechanised harvesting creates its own critical risks, particularly if machines and the people who operate them are working on steep and more difficult terrain. With winch-assisted technology now widely used around New Zealand, the forestry industry identified the need for a Best Practice Guide. This Guide will set a benchmark for winch-assisted harvesting on steep slopes. Safetree was pleased to be able to lead the development of this Guide, with funding support from ACC and WorkSafe. We would also like to thank the team of forestry, safety and machinery experts who volunteered their time and expertise to create this Guide. This Best Practice Guide will be maintained by Safetree and it is our intention to make updates as winch-assisted harvesting technology develops. Please provide any feedback you have to [email protected] Fiona Ewing National Safety Director Forest Industry Safety Council / Safetree Copyright PRINT: 978-0-473-63562-6 PDF: 978-0-473-63564-0 EPUB: 978-0-473-63563-3 May 2022 Acknowledgements Brett Gilmore was the author and collator, project managed by forest growers levy trust inc John Lowe. FISC appreciated the guidance from the steering group: Les Bak, Darin Borcorsky, Jackie Delaney, Wayne Dempster, Spike Edwards, Geoff Gover, Kerry Hill, Doug McCloud, Darren Tahere, Billy Tohaīa, Andrew Widdowson and Ian Wilton. Dr. Rien Visser, University of Canterbury, provided significant technical content and the guide’s technical review. Other guides and manuals were used including excellent resources from FPInnovations, BC, Canada. Special thanks to operators and loggers who provided expertise and feedback. Comments and suggestions to [email protected]. Disclaimer Winch-assist harvesting is now well established in New Zealand after rapidly expanding. The guide was developed using existing guides and manuals within New Zealand and overseas. The steering committee and steep slope harvester machine operators gave technical input. Scan to download The purpose of the guide is to promote best practice for winch-assist operations. Best practice changes and improves over time as winch- assist systems develop and knowledge and experience are gained. Legal obligations for companies, contractors and operators are set out in the Health & Safety at Work Act (2015) and specific guidance for Winch-assist in the Approved Code of Practice (ACOP) for Forest operations.  Steep Slope Harvesting Best Practice Guide 3 Contents Part A – The winch-assist system Chapter 1 Overview of winch-assist ground-based harvesting8 – What is winch-assist harvesting – Why use winch-assist systems Chapter 2 The operator12 – What it takes, from professional operators – What training you need – How to manage fatigue and emergencies – Ways to work with hand fallers Chapter 3 Winches20 – The different winch types and how they work – That traction aid is not winch-assist – Your machine skills could impact winch tensions Chapter 4 Steep slope harvesting machines30 – What is a steep slope harvesting machine and their features – What affects traction, and how a cable improves it – Things that affect stability – Ways to help reduce machine rollover Chapter 5 The anchor and repositioning40 – Different sorts of anchoring systems – Why anchors fail and how to stop this from happening Chapter 6 Rigging48 – About wire rope and the different connectors’ strength – Why bending a rope can severely damage it – Rigging guidance that needs to be followed Chapter 7 Common operational situations58 – Use redirects (rub trees or stumps) – Manage the boundary between winch-assist and hand falling – Anchor winch excavators on a narrow ridge – Uphill winch-assisted systems 4 Steep Slope Harvesting Best Practice Guide Part B – Other factors for a well run winch-assist operation Chapter 8 Risk assessment and management72 – Some of the hazards and risks you need to manage – Ways to reduce them – Some useful reference material Chapter 9 Steep slope harvesting and the environment84 – How winch-assist can affect the environment – Why winch-assist can create a lighter footprint on the ground than an unassisted machine – Ways to improve environmental outcomes Chapter 10 Stability and traction92 – How gravity changes stability – Things to watch out for that affect machine stability – How traction changes with slope and soil conditions – Why a winch improves traction Chapter 11 Planning winch-assist operations110 – What makes a good plan – Planning starts well before the felling starts and finishes after the machinery leaves – Your role in the planning process, whether planner, contractor or operator Chapter 12 Machine and rigging inspection, servicing and maintenance120 – Regular inspections for: – Winch-Assist Machine (WAM) – Supported machine – Ropes and connectors – Non-WAM anchors – Servicing, including annual inspections – Guidance to help safely undertake repairs and maintenance Appendix 1: References140 Appendix 2: Examples of steep slope risk assessments141  Steep Slope Harvesting Best Practice Guide 5 The Best Practice Guide’s purpose The purpose of this guide is to assist operators, contractors, and supervisors: 9 Improve understanding of winch-assist systems. 9 Guide what is best practice. 9 Help improve the safety of winch-assisted harvesting operations. 9 Achieve best environmental outcomes. 9 Improve productivity. Duty of care The Winch-Assisted Harvesting Best Practice Guide aims to contribute to a safer work environment. The Best Practice Guide helps fulfil the duty of care requirements within the H&S at Work Act 2015 on Persons Conducting a Business or Undertaking (PCBU). These require PCBUs to provide and maintain a safe work environment, safe plant and structures and safe systems of work. Everyone is required to play their part, including employers, workers, and machine designers and manufacturers. 6 Steep Slope Harvesting Best Practice Guide Symbols used in the guide Warnings: Warnings specify hazards associated with a task, location, or equipment. Experienced operators’ advice: Experienced operators’ have emphasised important information. Examples of good and poor practice:  Steep Slope Harvesting Best Practice Guide 7 Part A The winch-assist system 8 Steep Slope Harvesting Best Practice Guide Chapter 1 Overview of winch-assist ground-based harvesting  Steep Slope Harvesting Best Practice Guide 9 In this chapter you will find out: 9 What is winch-assist harvesting. 9 Why use winch-assist systems. What is a winch-assisted harvesting system? Winch-assist is a ground-based harvesting The Best Practice Guide uses the term system that uses wire rope(s) attached to winch-assist because it is in the Approved a machine to operate in a broader range Code of Practice for Health and Safety in of conditions, often on steeper slopes. Forest Operations (ACOP). The term A common New Zealand use of winch- traction aid, also widely used, has an assist is steep slope felling or shovelling important difference from winch-assist. with a tracked excavator. However, Traction aid uses a rope to support a a range of other machines can be machine capable of operating on the slope, successfully winch-assisted including but winch-assist gives access to terrain skidders and forwarders. Winch-assist that could not otherwise be operated is often called cable-assist or tethered. without the support of a winch and wire rope. 10 Steep Slope Harvesting Best Practice Guide Why use winch-assisted harvesting? A big drive has been to improve safety, productivity, operational flexibility, and forest owner returns. There is a global trend toward more mechanised harvesting systems. Winch-assist is specifically designed to extend the operating range of machines on steep slopes. Safety The supporting winch-assist machine may An initial driver for winch-assisted not always be required and often needs harvesting systems was to improve felling to be relocated, so their utilization is safety. Machines protect workers from likely lower than other machinery on a many of the risks associated with manual harvesting site. When done effectively, felling. The forest industry has invested there’s substantial productivity heavily in mechanisation, and winch-assist improvements and financial benefits. technology has been encouraged by forest Environment companies. WorkSafe’s position on new There can be environmental benefits, technology is that companies should adopt but this depends on the site and its it when it better manages risk. The move management. Winch-assist improves to winch-assist has been an important machine traction, and with good operators safety step to protect workers through and site conditions, deep soil disturbance is new technology. often significantly less than operating Cost and Productivity machinery without winch-assist support. On average, cable logging is more Where cable assist replaces cable logging, expensive than ground-based operations. less roading and landing earthworks may Winch-assisted harvesting increases the be required. operating range of ground-based However, winch-assist allows harvesting machinery. It can also be used to support machinery to operate on steeper slopes cable logging operation through where previously no machine could have mechanised directional felling for worked. Machines have a higher level of extraction, bunching and shovelling. soil disturbance and compaction compared Through careful planning, it can reduce to manual felling. However, soil type and infrastructure costs like roading, landing weather conditions, and operator skill play number and size. a big part in getting a light environmental However, there’s a significant capital footprint. investment and higher operating costs associated with winch-assist harvesting over other ground base operations.  Steep Slope Harvesting Best Practice Guide 11 System parts Irrespective of whether you are using the winch-assist system to fell, skid, shovel or forward, there are four essential parts. These are the: 1. Operator. 2. Steep Slope Harvesting (SSH) machine. 3. Winch on the harvesting machine or an anchor machine. 4. Rigging. A Winch anchor B Rigging C Steep Slope D The operator machine Harvesting (SSH) machine 12 Steep Slope Harvesting Best Practice Guide Chapter 2 The operator  Steep Slope Harvesting Best Practice Guide 13 In this chapter you will find out: 9 What it takes, from professional operators. 9 What training you need. 9 How to manage fatigue and emergencies. 9 Ways to work with hand fallers. Being a winch-assist operator is a including fatigue management, when to challenging job. It’s not for everyone. stop, and working alone. You are a professional in a million- Mechanised felling with a winch-assist dollar setup. machine is not possible everywhere, and This chapter covers the important aspects another critical part of this chapter is of having what it takes for the job, the working with the hand feller. training needed, and aspects of self-care, Having what it takes Experienced operators were surveyed anonymously on their views around what it takes to be a good operator. They said: 1. A planning mind, always thinking 5. Having patience and being calm multiple steps ahead. under pressure. 2. Trusting the machine and your ability 6. Always consider the whole job and 3. Knowing limits of the machine and ways to make it all go smoother. oneself. 7. Goal setting and taking pride in 4. Experience and competence, and your work. never complacency. 14 Steep Slope Harvesting Best Practice Guide Important messages experienced operators want to pass on 1. Check your gear and trust it – anchor, 7. Ensure you can see the ground, and electronics, rigging and machine! look up as well as down. 2. Work within your limits. 8. Make sure you can always get out of 3. Plan and have a Plan B. Be adaptive to where you’ve gone. changing situations. 9. Look how the winch rope(s) lay. That’s 4. There are places you don’t winch- where they take you back up the slope. assist. Don’t be forced to go there. 10. Know when to stop and leave the 5. Stay focussed. Take regular breaks and remainder for hand felling, even if it is stop operating if you’ve lost just a few trees. concentration. 11. Always keep things clean for the hand 6. Take your time. Don’t let production fallers, just in case they need to finish pressure affect your decisions. things off. Things that affect an operator’s work Headspace Hazard ID mind on task, avoids distractions, rushing, quality maps and felling plans, identifying complacency, or fatigue. changing conditions and unforeseen hazards; knows how to manage and when Attitude to stop. Knows when to ask for help. healthy knowledge and respect for hazards, listens to supervisor, follows plan. Equipment know the physical capabilities of each Competency machine and the harvest block. experience and skills with the machine, and harvest sites. Supervisor’s competency and attitude Planning understands the plan and how to time spent pre-planning, thinking about implement, recognises when adjustments next steps, adapt to change. are needed, acts to implement, communicates with the operator; avoids a production-only attitude. Delay steep slope work until a suitable machine or operator is available.  Steep Slope Harvesting Best Practice Guide 15 Winch-assisted operator’s training requirements Operators for winch-assisted felling are often trained and experienced mechanical felling operators. The operator, after training, must be able to: – Demonstrate knowledge, and safe – Describe factors that influence operation of the winch-assisted system. harvester stability. – Set up a new winch-assist line. – Minimise both total loads, as well – Conduct daily pre-start and as shock loading on the cable(s). maintenance checks. – Shutdown/isolate the winch system – Identify site hazards and describe how in an emergency situation. associated risks are controlled. General mechanised operator training requirements – The operator must be suitably trained receive adequate supervision. The or under supervised training. level of supervision is determined – The operator must have competency by the level of competency assessed regularly. The assessment demonstrated by the trainee. should be organized by the employer, or if self-employed, by the operator. The assessment should be undertaken by a person who sufficiently understands winch-assisted operations. – All training must be documented. – Trainee mechanised fallers must 16 Steep Slope Harvesting Best Practice Guide Unit standards for winch-assisted felling The following NZQA unit standards have been specifically developed for winch-assist systems: Unit Standard # Description 30583 Establish an anchor for cable-assisted forestry machine 30584 Demonstrate knowledge of cable-assisted forestry machine operation 30585 Operate cable-assisted forestry machine 30586 Manage cable-assisted forestry machine operation A fully trained operator, depending on the machine type and harvesting method, may hold the following NZQA Unit Standards: Unit Standard # Description 1231 Prepare wire ropes for harvesting operations 6935 Operate an excavator based tracked machine in a forestry situation 6941 Demonstrate knowledge of forest mechanised harvesting 6945 Fell trees using a mechanised harvesting machine 6947 Bunch tree lengths for extraction or processing 17771 Carry out line shifts in a cable harvesting operation using a mobile tailhold machine 22994 Demonstrate knowledge of factors that affect the performance of forestry workers 24590 Operate a self-levelling machine in a forestry situation 30587 Shovel and Bunch tree stems or logs  Steep Slope Harvesting Best Practice Guide 17 Some operators may not hold some unit standards, e.g. 1231 and 17771 in a groundbase crew. If the operator doesn’t have the specialist skills then someone trained or qualified should be available to assist, e.g. rope splicing or line shifts. Example – Winch-assisted operator training programme Winch-assist training typically starts will learning skills on mechanised felling machines, and as competency is reached, training is progressed to steeper terrain and finally to winch-assisted harvesting. Mechanised Faller Skill Development SBOs Frequency Classification and Supervision by Contractor Trainee Operator As a minimum the operator Training notes shall be kept. will have spent 20 working These should record date, Less than 6 months days (160 hours) felling/ training and observations. experience or 500 hours shovelling on slopes less on the machine. SBOs will occur monthly than 22 degrees before by a suitably qualified or Will be working towards undertaking further training experienced person. the following qualification: on slopes exceeding Forest Operations Advanced 22 degrees. The Contractor or plant – Mechanised Tree Felling. supplier will provide An Intermediate or reference material such experienced operator will as operator manuals to supervise and support until the trainee. competency is achieved. Intermediate Operator An experienced operator will Training notes shall be kept. supervise and assist. More than 6 months SBOs* will occur monthly experience and 500-1000 The operator shall be given for the first 3 months, then hours on machine. sufficient time to become quarterly by a suitably qualified familiar with a new machine’s or experienced person. controls and capabilities. The contractor will provide reference material like operator manuals to the trainee. Experienced Operator The operator’s competency is The Contractor or plant periodically assessed for by a supplier will provide > 12 months experience. suitably qualified or reference material like Holds a Forest Operations experienced person. operator manuals. Advanced – Mechanised Tree Indirect supervision is SBOs* will initially occur Felling certificate plus the provided to an experienced quarterly by a suitably winch-assist unit standards operator. qualified or experienced 30583-87, or be in a signed person until competency training agreement with a achieved. Then 6 monthly. provider to achieve these. * Top Spot assessments are equivalent to an SBO. 18 Steep Slope Harvesting Best Practice Guide Operator fatigue plan Winch-assisted harvesting can be It helps if you eat and drink well, have demanding, especially on steep ground a good night’s sleep, exercise, and take and in tough conditions. It is essential work breaks. to maintain concentration. A fatigue Get training on fatigue, so you know plan helps the operator manage their what to look for and how to manage it. work health and be ‘fit for work’. Safetree Fatigue Management Guidance safetree.New Zealand/wp-content/uploads/2016/11/Fatigued_-Or-Fit-for-work_-.pdf The following may help develop a fatigue management plan: – Incorporate a minimum 15-minute break every 3 hours or two 30-minute breaks per day. Microbreaks of 5 minutes per hour often work well. – Limit work to no more than: – 13 hours per day, excluding rest breaks, but including travel. – 65 hours in 7 days, including travel time. – 6 successive days. – Keep a log of hours worked. – Look after yourself. Take breaks and stop operating if you’ve lost concentration. – Do not operate the machine if fatigued. – Don’t do unsafe work, and don’t let production pressure affect your decisions.  Steep Slope Harvesting Best Practice Guide 19 Working alone procedure including a no response action plan Working alone is work done in a location The operator needs to: where a worker can’t physically see or talk – Confirm their point of contact and to other workers. This could expose them the contact’s location. to additional risk should the work go not as – Ensure that their whereabouts are planned especially where assistance from known. others is not readily available. An example of working alone in steep slope harvesting – Communicate their plans. is an operator pre-falling before the main – Have an RT or cell phone for crew set up at the harvest site. communication. A registered EPIRB gives an additional option. There must be a documented Working Alone Procedure, including a No Response – Make minimum hourly check-ins with Action Plan. The procedure must be known a contact person. and understood by the crew and – If the work plan changes, inform the operationally followed. contact person. A good place to confirm the plan for each day is during the tailgate meeting. Establish an alternative communication plan where there is poor cell phone reception. 20 Steep Slope Harvesting Best Practice Guide Chapter 3 Winches  Steep Slope Harvesting Best Practice Guide 21 In this chapter you will find out: 9 The different winch types and how they work. 9 That traction aid is not winch-assist. 9 Your machine skills could impact winch tensions. This chapter is about the winch. Not about how they are anchored or repositioned which is discussed in Chapter 5. What is a winch? A winch is a powered geared drum that Some drums pivot under load, which spools the wire rope. Winch systems can acts as a shock absorber within the have different mechanisms for managing rigging system. tension and power that aim to provide There are two options for the winch constant tension. The operator adjusts the location: winch settings. For example, some have the wire rope tensioned through constant – On the anchor machine. hydraulic pressure or band brakes applied – On the steep slope harvesting to the drum. or extraction machine. Winch Anchor Machines Anchors can range from small units that deliver a pulling power of 5 tonnes up to larger systems more common in New Zealand that deliver pulling of 18-23 tonnes. The advantage of the system is the: – Winch anchor machine is mobile and can assist with a line shift. The winch(es) are mounted and powered – Two machines can easily disconnect by a mobile anchor. The winch anchor so either machine can do other work machine is typically a modified excavator or work with a different machine, e.g. or a bulldozer. The complexity and cost the steep slope harvesting machine can of fitting a winch to the anchor machine shift between winch-assist and other make them purpose-built machines. operations. The harvesting or extraction is done by – Winch anchor machine can still operate a second machine working on the slope. as a dozer and or a digger. 22 Steep Slope Harvesting Best Practice Guide These are a few examples of commercial models available, top left: Eco-Forst T-WINCH 30.2. Top right: T Max. Below left: Electrical and Machinery Services (EMS) Tractionline and below right: DC Equipment’s Falcon winch-assist. Winch on the steep slope harvesting machine The second option is the winch mounted The advantages of the integrated systems: on the steep slope harvesting (SSH) – It is a one-machine system. machine. They can either be integrated – The rope doesn’t move along the into the chassis or have a winch mounted ground because the rope is spooled on onto the machine. It is a one-machine the SSH machine. winch-assist system when anchored to stumps or deadmen, although it can also – Flexibility in the anchor type, e.g. a be supported by a second anchor machine stump, deadman, or mobile anchor. that does not have the winch on it. The only New Zealand made winch integrated SSH machine is the ClimbMax. In Europe, most have the winch mounted on the SSH.  Steep Slope Harvesting Best Practice Guide 23 Left: ClimbMax Steep Slope Harvester. Right: HERZOG ALPINE Synchrowinch. Single and double rope (two-line) systems Winch-assist can be single or double rope systems. There are advantages and disadvantages in both systems, and the choice comes down to the merits contractors can see for their operations. Examples of double rope systems. Left: EMS Tractionline. Right: The Remote Operated Bulldozer ROB. The difference between ‘traction-aid’ and ‘climbing support winches’ The ISO standard 19472-2:2021(E) This is different from how many operators Machinery for Forestry; Winches – Part 2: use winch-assist in New Zealand. Winch- Traction aid winches was published in assist is often used to help access terrain January 2022. The ISO standard that would otherwise be impassable. The distinguishes traction aid winches and term 'climbing support' has been coined by climbing support winches, as seen in the the standards review committee to diagram below. Traction aid is where the differentiate between the ISO 19472 rope is added to reduce machine slip, but traction aid systems that have been the supported machine is both stable and designed, manufactured, and employed still able to move on the slope without in the northern hemisphere with those support from the rope. manufactured in New Zealand. 24 Steep Slope Harvesting Best Practice Guide The standard is significant because of the ropes rated breaking strength. The ISO implications around differences in the Safe standard allows for wire rope to be Working Load (SWL). The ACOP requirement operated at a tension up to 1/2 the rope’s is for a winch-assisted operation’s rigging minimum breaking strength, recognising it to be tensioned up to at least 1/3rd of the is only for traction aid. Tracve Effort Locaon Installaon Fixed installaon Intergrated in the supported machine Tracon Aid Winches (stable on slope without Removable rope support; main effort: slip reducon) Winches for Remote setup away from Self propelled, the supported machine Tracve Efforts working autonomously self anchored Climbing Support Winches (not stable on accessed slopes; main Mounted on effort overcome carrier machine otherwise impassable slopes); not covered in this standard Good winch features The following are good features for winches used in assisted operations. – A winch specific emergency stop – Chartered Professional Engineer procedure. or manufacturer certified winch – A pre-set maximum line pull that does attachment points and tow hitches. not exceed the safe working load of the – Systems that in ‘real time’ monitors, wire rope (33% of breaking limit). records and relays to the steep slope – A winch auto-stop mechanism designed harvesting machine cable tension and if the anchor machine loses power or winch rope details like rope off and when the drums’ minimum wire rope remaining on the drum. length is reached. – The manufacturer’s service schedule – A winch braking system can hold the for the winch and its ancillaries’ parts. steep slope harvesting machine if power, traction, or stability are lost.  Steep Slope Harvesting Best Practice Guide 25 Winch tension monitoring systems Cable-assist machines should have a tension 2. Measuring the hydraulic pressure in monitoring system. Wire rope has a Safe the winch drum. Working Load (SWL), and without a monitor, 3. Using a sheave in the rigging system, the tension in the rope cannot be managed. where the rope passes through a The operator needs to set the tension and known change in direction. view the current tension setting. All three require careful calibration to Like in cable logging, tension is difficult reflect the tension in the rope accurately. to measure directly as a load cell cannot Torque varies with the diameter of the easily be put into the rigging system, so winch drum. For example, when using monitors indirectly measure tension. hydraulic drum pressure, ‘the effective Three examples are: diameter’, or the number of wraps on 1. Putting a small deflection (‘bight’) the drum, must be calibrated correctly. in the rope using three sheaves and measuring the pressure on one of the sheaves. A three sheave deflection winch tension monitor system. 26 Steep Slope Harvesting Best Practice Guide Many factors affect winch tensions Winch-assisted operations are complex, A frequent cause of shock loading is lag and the forces involved are relatively large. in the system’s response time to machine The operator sets the desired tension. movement. While shock loading cannot be A good operating practice is to use the avoided entirely, understanding it helps to lowest possible winch setting required avoid overloading. The example winch- for the job. This creates the least amount assist tension graphs below show some of stress and risk in the system. limitations in managing tensions. Increased loading known as shock loading, can be common when using winch-assist. 1. Moving the machine causes most ‘shocks’ and not from felling or shovelling A Spikes are from the machine moving B Flat sections are the machine felling Figure 1 Tracked machines, especially when moving Also shown on Figure 1 is when the downhill, can generate a large pulling force machine was moving (orange line). This combined with traction and gravity! There confirms that nearly all sudden spikes are is often a small lag between when the from machine movements, not from the machine is pulling the rope, and when the felling or shovelling activity. winch can adjust its tension. This shows up on the tension charts as a spike with tensions going both up and down.  Steep Slope Harvesting Best Practice Guide 27 2. The tension depends on the operator setting A Machine working downhill B Machine heading up the slope Figure 2 Operators can choose from tension Figure 3 chart shows the operator of a settings as low as a few tonnes, all the way two rope system (blue and orange lines) up to the safe working load (SWL). changing their setting from about 4.5 tonnes up to 8 tonnes. For example, this Figure 2 shows the operator choosing a might be required as the slope gets steeper tension of about 6-7 tonnes while working or the soil conditions become wetter. The downhill, and then at the 20-minute mark, chart shows that dual-wire systems share increasing the setting to 18 tonnes to help the load evenly. the machine go back up the hill. This change in setting is much larger than the smaller shock loads. A Initial tension B Operator increased winch tension Figure 3 28 Steep Slope Harvesting Best Practice Guide 3. Extreme winch tensions do arise from operator errors Figure 4 and Figure 5 A Machine ‘stuck’ behind an obstacle B Operator had brake on and drove down the hill Figures 4 and 5 show that operator Right: The operator still had the system on decisions can potentially lead to serious a manual feed setting and began to move risk. Left: The steep slope harvesting the machine downhill. When the winch is machine was stuck behind an obstacle, either off or in a manual setting, the winch so the operator put the tension up to its won’t adjust to an increase (or decrease) in highest setting then used the boom to rope tension. The graph shows over 40 generate an extra force to solve the tonnes on the rope when both gravity problem. The graph spiked to 34 tonne, and the steep slope harvesting machine’s which is well over the SWL. traction were pulling on the winch. 4. Redirects (rub trees or stumps) Redirects add friction and result in the rope tension being different above and below the redirect. For example, if a winch applies a rope tension, the pulling power of the rope reduces after going around the redirect. See the section ‘How redirects change rope tension' on page 61.  Steep Slope Harvesting Best Practice Guide 29 Shock loading results in higher tensions than the operator setting. Guidelines when working with winches – Record winch operating hours for – Use a constant tension system. Never operational machinery and rigging. allow slack to develop in the line. servicing and replacement schedules. – Use a mechanism or system to prevent – Before operating, make sure all safety accidental operation of the assisted systems are operating. machine when the winch is in manual – Don’t override safety controls. mode. 30 Steep Slope Harvesting Best Practice Guide Chapter 4 Steep slope harvesting machines  Steep Slope Harvesting Best Practice Guide 31 In this chapter you will find out: 9 What is a steep slope harvesting machine and their features. 9 What affects traction, and how a cable improves it. 9 Things that affect stability. 9 Ways to help reduce machine rollover. What are steep slope harvesting machines? Steep slope harvesting (SSH) machines are Felling and processing SSH machines are purpose-built for working on steep slopes. either wheeled harvesters or a tracked In New Zealand, the most common winch- harvester/feller-director/feller-bunchers. assisted SSH machine is the excavator- They have either levelling or non-levelling based feller-buncher that has replaced bases. Levelling machines are more manual felling in many situations. comfortable than non-levelling, especially However, SSH machines can be skidders, when slewing during felling or shovelling. forwarders, excavators, and specialised Log or tree extraction SSH machines tracked or wheeled harvesting machines. typically are levelling, or non-levelling This leads to many makes and models. tracked excavator forwarders, wheeled SHH can have a chassis built on tracks forwarders, clam bunk skidders, or four or or wheels. The cab can often level. The 6-wheeled rubber-tyred grapple skidders. power unit may be part of the cab /upper structure or on the chassis. 32 Steep Slope Harvesting Best Practice Guide Excavator base vs wheeled machines In New Zealand, excavator-based machines In these situations, sudden loss of traction are commonly used for felling and and stability can occur. shoveling as they typically have more Wheels are better on undulating terrain. power, move larger trees, and have more A major advantage is getting over obstacles traction in steeper terrain or poorer soils. like stumps that excavator-based machines However, their rigid base reduces the struggle with. Wheeled machines tend to tracks contact on uneven terrain, such as have significantly better vision than when shallow rock is present. excavators because the boom is set high.  Steep Slope Harvesting Best Practice Guide 33 Levelling vs non-levelling cabs A levelling cab is essential for winch- Studies have also shown that productivity assisted operations on very steep slopes. and operability is enhanced when using a A leveling cab redistributes the centre levelling cab. of gravity uphill to improve stability, especially on slopes over 33 degrees (65 percent). It has been shown that they reduce rollover risk. Hydraulic rams A and a pivot B levels the cab. 34 Steep Slope Harvesting Best Practice Guide Machine features to safely and effectively work on steep slopes Steep slope harvesting machines are purpose built for their work environment. General operation A Engine designed B Cable C Minimum 2 D Adequate to work on the attachment (preferably 3) traction and maximum slope points emergency slew power for limit engineered for exits with two steep slopes the expected accessible from loads the outside E Fluid systems designed to operate on steep slopes Also: – Emergency back-up system to ensure stability should the winch, wire rope, or anchor fail. – Designed and tested to operate continuously for steep winch-assist.  Steep Slope Harvesting Best Practice Guide 35 Cabin A Fully B Minimum C Comms system D Fire integrated/ four-point seat extinguisher automatic fire belt harness (lap suppression 75mm + system shoulder 50mm) Also: – Noise levels less than of 85 dBA otherwise hearing protection. – Aircon (15-25oc). – A place to secure all water and food containers. – No loose or dangerous material inthe cab. 36 Steep Slope Harvesting Best Practice Guide Upper structure – external A Compliant forestry cab with ROPS, B 19mm polycarbonate or equivalent FOPS, and OPS front window Also: – Over-riding and functional braking system in the event of loss of machine power. – Guarding that protects the steep slope harvesting machine’s mechanical operation. – Company safety/emergency stickers.  Steep Slope Harvesting Best Practice Guide 37 Undercarriage Extended (>50mm) single grouser track shoes for tracked machines and chains or bands for rubber tyred machines. Machine attachment points A low frame-mounted attachment point is Sharp edges can damage the rope or chain usually best. Do not sling around the lower and the machine structure could also be structure. damaged. Cable attachment points engineered for the A certified heavy duty towing hitch. expected loads. 38 Steep Slope Harvesting Best Practice Guide A Risk of extreme side loading of chain link Electronic systems The following are recommended: – A winch monitor, with audible alarms, – Hour meter that tallies the number of showing the hydraulic temperature or hours the winch and cable operated to over-temperature light, cable tension monitor cable use and life. and overloads, remaining available rope length, and when the minimum number of cable wraps is reached, rope length in use and spooling errors. Remote control systems that incorporate safety Prevent accidental operation of the Steep redundancies. Slope Harvesting machine when the winch is in manual mode.  Steep Slope Harvesting Best Practice Guide 39 Inclinometers can have digital readouts or mechanical. Camera display of obstructed view areas for the operator including winch. Take care of aerial and electronics, they can be damaged. 40 Steep Slope Harvesting Best Practice Guide Chapter 5 The anchor and repositioning  Steep Slope Harvesting Best Practice Guide 41 In this chapter you will find out: 9 Different sorts of anchoring systems. 9 Why anchors fail and how to stop this from happening. Types of anchors Stumps Stumps have been very commonly used in alarm signal should the stump start to cable logging operations and are an option move. There needs more research on for integrated winch-assisted SSH stump anchoring for SSH machines as machines. Refer to section 14.3 of the stump requirements have come from cable ACOP. Regularly inspect stumps because logging operations. For example, the need they can work loose under shock loading. for notching stumps with synthetic strops Stump monitors give the operator with an for SSH application. A Minimum stump diameter of 500mm B Only use fresh stumps in strong soils C All stumps must be notched D 30cm of solid wood above the notch D Also: – A stump monitor alarm should be fitted. Shock loading stumps can loosen or pull them out. 42 Steep Slope Harvesting Best Practice Guide Deadmen Deadmen, like stumps, can also be used to anchor integrated winch-assisted machines. Deadmen are typically strong if installed in accordance with section 14.3.5 of the ACOP. A Dig the trench B Make at least C Lay a strop in D The strength at right angles 4 m deep and the trench rating of the to the pull about 7 m long deadmen strop should be at least equal to the winch rope F E G H E Use green logs F The notch G The two strop H Compact as at least 50 cm stops the log ends must be you backfill in diameter being pulled equal before straight up shackling Rocky soil and fill can cause strops to wear and fail. Always use suitable fill and periodically check strops.  Steep Slope Harvesting Best Practice Guide 43 Anchor machines These are either bulldozers, excavators, bring the rope close to the ground and or purpose-built winch anchors. Machine significantly reduce any lateral instability anchors are popular because they are issues. The bucket is dug into the ground mobile. This means the steep slope to provide the extra holding strength harvesting machine can quickly shift required to make it a safe anchor. A between winch-assist and other operations significant advantage is that they can lift without modification. the rope for a line shift. The most common anchor in New Zealand Bulldozer anchors have a sturdy base is an excavator. The winch(es) are mounted and low centre of gravity. The blade must at the machine’s rear, with the wire rope(s) be pushed into the ground to provide coming up over the top of the boom. the extra strength as a solid anchor. If positioned correctly, the bulldozer blade The two largest excavator-based winch- will move deeper into the ground if pulled assist manufacturers, DC Equipment and forward, so the holding strength increases EMS, have an additional sheave mounted with minor movement. on the boom just above the bucket to Left: the single winch DC Equipment’s Falcon winch assist. Right: The twin drum EMS Tractionline. Below left: the Remote Operated Bulldozer (ROB). Below right: Eco-Forst T-WINCH 10.2. 44 Steep Slope Harvesting Best Practice Guide Why anchors fail The following things can make anchors fail: If the soil is weak, there are three common – Poor anchor positioning, including an ways to strengthen the anchor: anchor machine not on level ground – Put the blade into the ground behind and blade or bucket not dug in correctly. a stump. The holding strength of the – Weak soil strength. stump will improve anchoring. Not too close behind the stum. Otherwise, the – Overloading the anchor. root system could get cut, and this – Anchors aren’t strong enough. gives the stump its strength. – SSH machine pulling from a too – Tie off to a stump behind the machine. wide lead angle. – If an excavator, reposition the bucket – Shock loading from the steep slope deeper or in a different location. harvesting machine. Most anchoring failures are a combination of factors – poor machine positioning or cable angles, and high loading. Guidance for safe machine anchoring A Install a tension B Use camera(s) C Use an anchor D Position safe monitor that to show steep movement and securely, relays to the slope harvesting alarm eg. avoid soft steep slope machine road or landing harvesting operator cable edges machine spooling operator  Steep Slope Harvesting Best Practice Guide 45 Do not exceed the anchoring capacity of the anchor machine. Improve by anchoring back to stumps as well. Don’t move the anchor and steep slope harvesting machine at the same time. One machine needs to be stationary and stable during line shifts. This bucket and blade should have been in deeper. 46 Steep Slope Harvesting Best Practice Guide Additional guidance for excavator anchors E A Dig bucket into B Bucket can be C Lead angle D Low cable firm soil so it normal way or within exit points won’t pull out reversed manufacturers to prevent limits overturning E Boom and stick angle between 90-110 degrees Machine anchors do move. Put the blade or bucket behind a stump. Check the anchor is holding each set up. Do a straight pull test.  Steep Slope Harvesting Best Practice Guide 47 Repositioning the anchor The anchor often needs repositioning to help keep it in line with the steep slope harvesting machine as the block progressively gets felled. Anchor lead angle The lead angle is typically the angle from the anchor’s fairlead to the steep slope harvesting machine. A Reposition the anchor or use rub trees to maintain correct lead angle B Maximise in-line pull. Minimise the amount of side pull 15° C Follow any manufacturer’s 15° specifications about the horizontal and vertical lead angle Guidance on the lead angle for an excavator There’s no one answer. It depends on the site and the current conditions, the machine, and how the machine is anchored. Follow the manufacturer’s specifications on the horizontal and vertical lead angle of the cable exiting the fairlead. Lead angle Soil type Comment Up to 15 Loose or Maintaining bucket stability is a limiting issue. degrees uncompacted fill Up to 30 Good Keep to this limit when operating for longer periods degrees as the soil may loosen over time. Also, for steep slopes when higher shock loading might be expected. Up to 40 Good The anchoring hole is deep enough (approx. 1.25m), degrees the soil is strong, and the machine is designed for the forces. Up to 90 Very strong Increasing sideways forces could generate forces degrees large enough for failure on the bucket/boom/ sheave unless manufacturers have modified their equipment design to accommodate such large angles. 48 Steep Slope Harvesting Best Practice Guide Chapter 6 Rigging  Steep Slope Harvesting Best Practice Guide 49 In this chapter you will find out: 9 About wire rope and the different connectors’ strength. 9 Why bending a rope can severely damage it. 9 What rigging guidance needs to be followed. Rigging connects the anchor to the steep slope harvesting machine. This chapter describes the different parts of the system. Parts of a rigging system A rigging system has several main parts. shown. Rigging is only as strong as These are the winch, wire rope, chain, its weakest link, so all components connectors, and shackles. There are many need matching with their strength different options, and some of these are characteristics. 1= winch, 2= rope, 3= rollover shackle, 4= hammerlock, 5= chain, 6= chain shackle, 7= steep slope harvesting machine shackle. Rigging is only as strong as its weakest component. 50 Steep Slope Harvesting Best Practice Guide Wire Rope This section describes the basics around wire rope and guidance around its use. Chapter 11 covers wire rope inspections and maintenance. Nearly all ‘wire rope failure’ incidents are caused by failed end connectors, failure due to poor practice like overbending the rope, or equipment design problems. Parts of a wire rope A rope consists of individual wires twisted The core supports and maintains the shape into strands. These preformed strands are of the rope. The rope’s cable ‘lay length’ is then twisted around the core to complete one full twist of the rope which is about the rope. 15cm for a 1 inch or 1 1/8th inch rope. A One cable lay length Different ropes, different properties Ropes behave differently depending on – Strength increases through larger construction. The combination of the diameter ropes or swaging. above factors creates ropes with varying – Abrasion resistance, or the outer properties. There are four fundamental wires’ ability to resist wearing away properties to differentiate rope: strength, and deformation, increases by abrasion resistance, crushing resistance fewer or larger outer wires, Lang lay and fatigue resistance. construction and higher carbon content in the metal.  Steep Slope Harvesting Best Practice Guide 51 – Crushing resistance, or the ability – Fatigue resistance, or the rope’s ability of the rope to resist deformation, is to resist bending and twisting, is improved with a strand or IWRC core, increased by more wires, smaller wires, swaging, and higher carbon content fibre cores, and Lang lay construction. in metal. Use the manufacturer’s specified rope. Wire rope strength and the safe working limit A rope’s strength will depend on its Definitions properties and type. All ropes have a Safe Working Load: Refers to the breaking strength rating. maximum weight a wire rope can handle The ACOP provides the following without the rope incurring damage. It is guidance: currently 33% of the rated breaking load. – The SWL to have a factor of safety of Endurance Limit: Occurs at 50% of the three – so the SWL is one third of the wire rope’s minimum breaking strength. rope’s breaking strength. When a rope is strained repeatedly past – Operations not to exceed the SWL. this limit, it reduces lifespan, and failure may occur even if the tension does not 115% Actual Breaking Load reach the elastic limit or breaking strength. 100% Rated Breaking Load Elastic Limit: The load limit at which the wire rope will, when the load is removed, 65% Elas c Limit return to its original length without 50% Endurance Limit incurring damage. It is defined as 60 to 65% 33% Safe Working Load (SWL) of the minimum breaking strength. If a strain is applied beyond this limit, the wire rope is damaged immediately, e.g. if the SSH moves without the WAM engaged. For SWL = Breaking load / 3 a larger shock load that exceeds the elastic limit, cease operations and replace the rope. Wire rope and bending fatigue Bending occurs when it goes around This happens because of the difference something including block sheaves, in diameter between the inside and the redirect stumps and logs. Bending can outside of a rope. Bending wear on blocks significantly increase the stress on the increases exponentially as the ratio of rope because the many wires that make up the sheave diameter to rope diameter the rope are forced to stretch at different decreases. rates when going around the bend. 52 Steep Slope Harvesting Best Practice Guide Follow manufacturers’ directions, or if For cable logging applications, a block unavailable, a minimum sheave to rope diameter of 20 times the diameter of the ratio of 16 :1 is recommended. rope is often recommended to keep the additional stress to about 10%. Such a Bending also increases the tension in the stress loading needs to be included in rope due to the rope tension plus the force the factor of safety. created by the bending. Shock loading, redirects, and bending can all increase rope tension beyond the SWL. Sheave/Rope Tension in outer wires Diameter Ratio of rope Small diameter ratios 10 times +27% create an unacceptable increase in stress 12 times +21% 14 times +17% 16 times +14% 18 times +12% 20 times +10% 24 times +8% Acceptable diameter 30 times +5% (account for in the SWL) Bending creates an uneven stretching of the rope. The tighter the bend, the more rope damage. Wire rope and ground contact Ideally, wire rope should not have ground However, depending on anchor placement contact. However, initial rope testing and system type, the winch-assist rope research showed that external wear from is dragged often through the edge of ground contact does not significantly landings and roads. This is because the affect winch-assist rope due to winch- anchor machine needs to sit back far assist ropes moving at relatively low enough so the steep slope harvesting speed. The rope is also on top of the machine can be lowered off the slope, ground with no sharp angles. and the road and landing edges often lack anchoring strength because they are in fill.  Steep Slope Harvesting Best Practice Guide 53 Also, this creates an erosion and Pulling a rope through the ground runs sedimentation problem if the site the risk of it bending sharply around a is not remediated. hidden rock (or similar), or that grit/clay works its way into the rope, decreasing its useable life. A Ropes are carving through bund B Rub logs help keep the rope above dirt and landing fill Guidance for wire rope – Visually check all connections daily. – Avoid cable drag over abrasive surfaces – If a sheave is used, make sure they have like rock and through the soil. a minimum of 16:1D/d ratio. – Minimise shock loading. Shock loading – Joining splices should not be used to rope and rigging reduce its life. repair broken or damaged winch ropes. – Wire ropes used for winch-assist – Use blocks where possible. Avoid should not be used for log extraction or running wire over sharp bends or hauling. redirect stumps or trees. – Review tension log data daily and whenever shock loading is known or suspected. Stop operations and inspect the wire rope for damage. Beware of shock loading or dragging a cable over rock. 54 Steep Slope Harvesting Best Practice Guide Connectors Connectors are used to join the wire There are various types and most have rope to the anchor and the steep slope advantages and disadvantages. There is harvesting machine. no ‘best’ connector. Common end connection options Left: The stopper should be to the right of the second or slave ferrule to stop it from being forced into the block. A challenge with pressed ferrules is that the soft ferrule metal wears easily if dragged along the ground. A Ensure that cable connections do not contact sheaves Always grommet or bolt shackle ends.  Steep Slope Harvesting Best Practice Guide 55 Logger’s eye splice The logger’s eye splice is the most common However, the spliced eye is not the end connector in winch-assisted harvesting strongest connector (~80% efficiency). operations due to quick splicing time and its Using a thimble adds strength and popularity in cable harvesting operations. prevents eye deformation (up to 90% It also pulls easily through the block and is efficiency). Balancing strands is not as easy to inspect. critical as thought. Eye splices failed at the last tuck at similar tensions, whether balanced or not. Logger’s eye with rollover shackle and hammerlock link. Tuck loggers eye splice three times on one side and two on the other (ACOP). Ensure no eye-to-eye splices. Different connector’s strength compared to the wire rope DIN 3093 Aluminum Splice with HD Thimble Open Swaged Socket DIN 3093 Aluminum Splice with Solid Thimble Closed Swaged Socket 56 Steep Slope Harvesting Best Practice Guide Flemish Eye with steel sleeve UNI-LOC™ Button Flemish Eye with steel sleeve and HD Thimble UNI-LOC™ Threaded Stud Flemish Eye with steel sleeve and Solid Thimble Forged Wire Rope Clips Open Spelter Socket (Closed not shown) Wedge Socket  Steep Slope Harvesting Best Practice Guide 57 Shackles Shackles need to be rated to match the SWL requirements for the rope. The safe working load, the Working Load Limit (WLL) is marked on the shackle. Use shackle with visible WLL markings. Guidance for connectors – Check end connectors daily. – Anchor strop strength must be equal – Use a rigging register. Maintain a or greater than that of the winch rope. schedule and document inspections, – Ensure that cable connections do not maintenance, replacements and contact sheaves. Use a second pressed incidents. The register must list each metal ferrule where the ferrule could component’s rated breaking limit, the run into blocks or sheaves. SWL and the safety factor. – Use a heavy-duty chain segment to – Every connector’s rating must match or prevent or reduce wire rope wear close exceed the wire rope safe working load. to the steep slope harvesting machine. – All rope eyes must be married and – Replace rigging as per the spliced with a minimum of three manufacturer’s requirements. tucks per strand. – Prevent shock loading to the wire rope – An approved wire rope company must and other system components. form swaged eyes. 58 Steep Slope Harvesting Best Practice Guide Chapter 7 Common operational situations  Steep Slope Harvesting Best Practice Guide 59 In this chapter you will find out how to: 9 Use redirects (rub trees or stumps). 9 Manage the boundary between winch-assist and hand falling. 9 Anchor winch excavators on a narrow ridge. 9 Use uphill winch-assisted systems. Redirects (rub trees or stumps) It is best to stay in lead by moving the They are also commonly referred to as anchor machine. Sometimes this is not rub trees or stumps or ‘side-washing’ in possible, e.g. in broken country with side North America. Redirects help maintain ridges. Most operators use redirects. the felling machine directly up and down the face. Some manufacturer guidelines specifically allow for it but give restrictions. A Redirect stumps and trees B High redirects are more likely to cause falling or leaning trees 60 Steep Slope Harvesting Best Practice Guide Redirects help: – Maintain a proper lead angle. – Control where and how the SSH – Enable the steep slope harvesting descends and ascends a slope, machine (SSH) to cover more ground e.g. when there’s broken ground. each machine anchor shift as multiple corridors are worked without moving the machine back to the anchor. Hazards created by redirects A Redirects can cause the rope to cut / bind B Redirects can create high temperatures from friction Also, redirects can: – Move or fail, causing a wire rope shock load, or steep slope harvesting machine instability. – Binding can lead to rope tension being different above and below the stump, causing inaccurate tension readings. – Increase hazard zones, e.g. rub trees.  Steep Slope Harvesting Best Practice Guide 61 How redirects change rope tension Redirects add friction and result in the restricting its free movement. This means rope tension being different above and more tension is below the stump than below the redirect. For example, if a winch above it at the winch anchor machine. applies a rope tension, the pulling power This is because the winch can still spool off of the rope reduces after going around a rope unrestricted. Don’t use higher tension redirect. The greater the redirect angle, settings when moving downhill and using the less tension goes to the SSH when a redirect. being pulled uphill. In the table below, if the winch is set at 20 The stump’s friction takes 25% of the tonnes and there is a 30-degree redirect, rope’s tension under load. However, if the the actual tension on the cable below the SSH is moving downhill, the machine has setup could be 25 tonne so operating to drag the rope around the stump that is above the ropes safe working load. When machine is tracking downhill The table gives indicative tensions only. Other factors can affect tension too. 62 Steep Slope Harvesting Best Practice Guide Working in steep broken country that requires redirects Working in steep broken country is challenging even for skilled operators. An example would be a steep face with lots of narrow gullies. The steepness makes the SSH machine have less traction, and the narrow gullies need redirects, so the machine is going up and down them, not sidling. Position the rope carefully to avoid unintentional redirects. A Use a redirect on the left side of the ridge if going right, otherwise there will not be enough room for the machine to pull up and over the ridge coming back up. B Re-cut stumps low on narrow ridges. C On ridges with flat sections, use redirect trees, otherwise the ropes will ride off the stumps. Two tree lengths apply for standing trees. Stump failure increases the risk of rollover if redirecting across a steep side ridge. Watch where your rope(s) run and what they run over. Wherever the rope runs that’s where they will take you back up!  Steep Slope Harvesting Best Practice Guide 63 Moving up, then getting the rope over a redirect no longer needed Coming back up the winch rope in steep On steep country rigging is usually lifted and broken country creates additional over stumps with the attachment. Weight challenges. Redirected ropes need lifting needs taking off the winch rope. Be aware over stumps. In easy country, this is that redirect binding creates tension in straightforward. The machine moves the rigging. Spooling off rope can create around them or lifts the rigging over them. significant hazards at the winch anchor like misfeeding and ropes riding off In steeper country, this can be much sheaves. Ropes get cut this way. harder. Carefully plan where your redirects are placed. For example, use a redirect on After spooling off a little slack, use the the left side of the ridge if you’re heading head to create slack at the rigging. Then right. Otherwise, there is not enough room lift over the redirect stump. for the machine to pull up and over the ridge coming back up. If the stump is too close to the ridgetop, it becomes difficult to get up and around it safely. A Don’t spool off too much. Slack can cause the wire not to feed correctly onto the fairlead sheave(s) as seen on two different machines. This can cut the rope. Take care when shifting off redirects. Binding from redirects significantly reduces anchor winches pulling power. Ensure you can climb back on top of the ridge by using a redirect stump, and not left hanging off to the side. In difficult country, ensure you can get out of where you went down. 64 Steep Slope Harvesting Best Practice Guide Redirecting using blocks Blocks reduce: – Friction and don’t create the changes in tension like stumps or rub trees. – Rope wear. – Permanent rope damage like twisting which may affect rope life and spooling onto the drum. Blocks can be challenging to manage, especially on twin rope winches where there is a need for double blocks. Also, multiple stump redirects are difficult, as is re-shifting winch ropes when moving back up the rope. If the block is attached to a looped chain, then the SSH can carry it and put over a stump. It can then also be lifted back over the stump when the SSH returns uphill. Use blocks rated for the expected load and forces, e.g. uphill winch-assist systems. Ensure block redirects are correctly installed. Use a block with an attached looped chain for redirects  Steep Slope Harvesting Best Practice Guide 65 Guidance for redirecting A Use stumps that are large and strong so they won’t move and create rope bending fatigue. B Position the rope low. Also: – Avoid redirects during high fire hazard. – Consider using blocks with redirect trees. – Check a redirect stump frequently, to confirm its stability. A Use multiple stumps or stems. A single stump failure could result in shock- loading. Even though multiple redirects will cause rope wear and reduce anchor winch power, it is safer than a single stump. B Position the winch rope to avoid unintentional redirects. C Avoid using trees. They can be more unstable than stumps. D Keep the redirect angle as wide as possible. Minimise using standing trees for redirects. 66 Steep Slope Harvesting Best Practice Guide Avoid angles over 45 degrees. Stumps can pull out or cut through. Managing the boundary between mechanised and hand felling In steeper and more challenging broken Guidance for managing the country, mechanised felling may not be boundary where hand felling safe or possible. This could include follows mechanised inaccessible anchor locations or areas below bluffs, rock or terrain that Managing the boundary between mechanised machines cannot go on, mechanical and hand felling is essential. or slopes exceeding 45 degrees. This is – Communicate the harvest plan with considered the absolute upper limit for any the hand fallers and involve them in winch-assist operation. The felling plan the planning processes. needs to identify hand felling areas. It isn’t – Map out the area to be hand felled. always clear, especially if the boundaries – Have the hand fallers work first if aren’t obvious ones. possible. Ideally, the hand fallers fell before the – Minimise ‘unnatural hazards’ if the hand winch-assisted operation starts in the fallers come in last. These are hazards setting. However, often it isn’t until the that have been made by the winch- winch-assisted machine is on the slope assisted machine that would otherwise that the operator can work out the hand not be there. felling boundary, leaving the hand felling until later. Otherwise, if hand felling occurred first, the winch-assist operator may not harvest all the remaining trees.  Steep Slope Harvesting Best Practice Guide 67 Always make boundaries as safe as possible for the hand fallers. A Keep hand B Fall away from C Leave a clean boundary canopy, with fallers escape the boundary. minimal broken branches. These are routes open on No branches or hard to see because they are still green the boundary tops in the hand falling area Also: – Redirect (rub) trees must be felled by the winch-assist machine. – Remove risks identified by hand fallers. – Eliminate other hazards that could be between standing and felled trees. – Inform the hand fallers of boundary hazards. Have the hand fallers work first if possible. Even when you think you can get all the wood, fell as if you might not. 68 Steep Slope Harvesting Best Practice Guide Anchoring excavators on narrow tracks or ridges Narrow ridges are common in many parts – Digging the bucket deeper and using of New Zealand and can cause difficulty solid ground creates more holding force when setting up winch-assisted machines. – Locating the bucket further back from There is not enough space for the winch- the edge improves holding force and anchor machine to be in line with the steep the rope will cut through the ground. slope harvester (SSH) requiring an alternative anchoring method. Increasing sideways forces could generate forces large enough for failure on the A solution is to sit the excavator perpendicular bucket/boom/sheave unless manufacturers (90 degrees) to the lead angle and use the have modified their equipment design to bucket to redirect the load from the SSH. accommodate such large angles. Unlike the standard winch-anchor machine anchoring where the anchoring is through It may also be challenging for the SSH machine, boom and bucket, most of the machine to access on or off the ridge. rope’s force goes on the bucket: A solution is to sit the winch-anchor machine far enough back or use redirects. – The strength of the soil that the bucket is dug into holds the SSH machine’s forces A Excavator is back far enough to allow B Ensures the bucket is in strong natural the felling machine to be on the rope as soil or in hard ground on a track it moves over the edge The orange wedge of soil holds the force from the steep slope harvesting machine!  Steep Slope Harvesting Best Practice Guide 69 The soil around the bucket is susceptible to loosening over time. Use solid ground and not uncompacted fill. Uphill winch-assisted systems Depending on the location, a common This occurs for many reasons including situation is where a mobile machine cannot crossing into a different property, no access the top of the winch-assisted physical way of access, environmental harvesting slope or cut an access track. reasons, or a different age class of trees. Winch on the steep slope harvesting machine Steep slope harvesting (SSH) machines – Drag strawline directly from the SSH with winch mounts, like the Climbmax to the stump. can use suitable stump(s) or tree anchor(s). – Pull up the winch line. This is a system advantage. – Securely anchor and back up anchor, if needed. – Attach a stump movement monitor. Winch anchor machines (WAM) A solution for WAM machines is for the winch rope to be fed through blocks at the top of the winch-assist harvest area back to the SSH machine. The system integrity depends on the: – Quality of the stump or tree anchors. Each anchor may need to have backups, e.g. 2 or more stumps – Using correct rigging, e.g. the right size and type of blocks, shackles, and strops Forces on the anchor and rigging are significantly increased. If a single anchor was used, and the tension on the SSH machine was 18 tonnes, then the force at the stump, block, strops, and shackles would be double at 36 tonnes. 70 Steep Slope Harvesting Best Practice Guide Anchor or anchor rigging failure may result in SSH machine destabilisation or rollover. Work area exclusion zones Operational work exclusion zones differ Minimum 20m depending on the harvest site. These – Either side of the winch rope should be determined as part of the site if operating without redirects. safely plan. The following are indicative work area exclusion zones. – Beyond the extent of the bight if using redirects (see diagram). Minimum 6m – Behind and to the side of a stump or deadman anchor. – Around the winch anchor machine. – Around the SSH machine (depending on the operation). Serious hazards exist from winch-assisted harvesting rigging and system.  Steep Slope Harvesting Best Practice Guide 71 Part B Other factors (for a well-run winch-assist operation) 72 Steep Slope Harvesting Best Practice Guide Chapter 8 Risk assessment and management  Steep Slope Harvesting Best Practice Guide 73 In this chapter you will find out: 9 Some of the hazards and risks you need to manage. 9 Ways to reduce them. 9 Some useful reference material. Hazards and risks Hazards have the potential to cause harm Risk considers both the likelihood and including serious injury or death. consequences of exposure. Risks can be to people, environment, and property. Risks are what could happen if someone is exposed to a hazard. Risk management process The risk management process should include the following steps: Idenfy Hazard Review/ Assess Monitor Risks Control risks (if unable Eliminate to eliminate) A risk assessment will help decide: – How severe is a risk. – How likely it is to occur. – Whether existing control measures are effective. – What additional action needs taking. – How urgently it needs doing. 74 Steep Slope Harvesting Best Practice Guide The following table provides information on each of the steps in the above diagram. Process Consideration Identify Hazards Find out what could cause harm or damage to people, property and the environment. For example: – Physical work environment including site factors – People and tasks – Work design and planning – Plant and equipment Assess Risks Understand the harm that could be caused by the hazard, how serious the harm may be, and the likelihood of it happening. Eliminate Risks It is best to try and eliminate risk. If eliminating the hazards and associated risks is not reasonably practicable, you must minimise the risk by one or more of the following control methods: Control Risks If it is not reasonably practicable to eliminate the risk, implement effective control measures to minimise risk. (Refer to the hierarchy of control measures in the above diagram). Ensure the controls are: A Fit for purpose B Suitable for the nature and duration of the work C Installed, set up and used correctly D Understood by those exposed to the hazard. Also consider whether your preferred control measures introduce new hazards or unintended consequences. Monitor / Monitor controls, and periodically review them. This helps ensure they Review remain fit for purpose, are being implemented correctly and are working effectively. Also, consider if there are any new risks. Where relevant and available, reviews should include inspection, consultation, testing and analysis of records and data.  Steep Slope Harvesting Best Practice Guide 75 Potential hazards G A Native B Soil and rock C Rivers and D Diameter and vegetation and type wetlands height, and fish habitat spacing of the trees E Steepness and F Amount of G Rolling debris ruggedness of rainfall and the area storms 76 Steep Slope Harvesting Best Practice Guide Risk likelihood/consequence matrix A common way to determine the likelihood and consequence of a risk is through a standard risk matrix. It is a way to assess the potential seriousness of a possible incident. Once the risks are understood, appropriate controls or protection can be put in place. The greater the risk, the stronger the controls need to be. The following is an example of a risk matrix. Likelihood Increasing Almost Negligible Unlikely Possible Likely Certain Certain Catastrophic Medium High Extreme Extreme Extreme Extreme Consequence Increasing Extreme Medium Medium High High Extreme Extreme Major Low Medium Medium High High Extreme Moderate Low Low Medium Medium High High Minor Low Low Low Low Medium Medium Insignificant Low Low Low Low Low Medium  Steep Slope Harvesting Best Practice Guide 77 Bowtie risk assessment The bowtie diagram is a form of risk Preventative controls on the left side assessment. It helps to visualise the interrupt the threat so it either does not risks, causes and controls on a single page. occur, or if it did, does not result in an injury or machinery damage. For example, The centre of the bowtie is a main hazard. in the top left gold box is poor site To the far left are potential threats or conditions and weather. There’s several causes for the central hazard. To the far preventative measures that include right are potential consequences if the stopping work by either not working or central hazard happened. For example, moving to safer part of harvest area. in the bowtie diagram below, injury and Recovery controls on the right side make machine damage can be caused by weather sure that if the central hazard does and site conditions, who is doing the work, happen, it either does not escalate into an how it’s planned and what equipment you actual incident, or if it did, the impact of are using. As a consequence of injury and the incident is minimised. For example, the machine damage is a trapped or injured