Mine Design PDF

I. Mineral Resources and Ore Reserves o Inferred Mineral Resources should not be directly converted into Ore Definitions: Reserves....

I. Mineral Resources and Ore Reserves o Inferred Mineral Resources should not be directly converted into Ore Definitions: Reserves. o A Mineral Resource is a o Ore Reserve estimates should not concentration of material with be aggregated with Mineral intrinsic economic interest that has Resource estimates in public reasonable prospects for eventual reports. economic extraction. II. Mine Planning Process o An Ore Reserve is the economically mineable part of a Measured or Phases: Indicated Mineral Resource, o Planning Phase: This is a critical including diluting materials and phase where a deposit is evaluated allowances for losses during mining. for its economic feasibility. It includes Categories of Mineral Resources: a conceptual study, pre-feasibility study and feasibility study. o Inferred Mineral Resource: Quantity and grade are estimated ▪ Conceptual Study with a low level of confidence. (Preliminary Valuation): Identifies potential o Indicated Mineral Resource: investment opportunities by Quantity, density, shape, physical comparing different methods, characteristics, grade and mineral defining the project's scope, content can be estimated with and using historical data for reasonable confidence. cost estimates. o Measured Mineral Resource: ▪ Pre-Feasibility Study: Quantity, density, shape, physical Determines if the project characteristics, grade and mineral justifies a detailed feasibility content can be estimated with a high study. Important sections level of confidence. include the aim of the study, Categories of Ore Reserves: technical concept, findings, ore tonnage and grade, o Probable Ore Reserve: mining and production Economically mineable part of an schedule, capital and Indicated (and in some cases operating cost estimates, Measured) Mineral Resource, with a revenue estimate, taxes and lower level of confidence than financing, and cash flow Proved Ore Reserves. tables. o Proved Ore Reserve: Economically ▪ Feasibility Study: Provides mineable part of a Measured Mineral a conclusive technical, Resource, with a high level of environmental, and economic confidence. base for making an Key Differences: investment decision. This involves optimizing all critical o Mineral Resources are categorized project elements, including by geological confidence while Ore production capacity, Reserves are categorized by technology, investment and economic viability. production costs, sales revenues and return on o Ore Reserves are a subset of investment. It serves as a Mineral Resources, derived after baseline document for project considering Modifying Factors such advancement and should as mining, metallurgical, economic, include all detailed marketing, legal, environmental, information. social, and governmental aspects. o Implementation Phase: Involves o The terms "ore" and "reserves" the development of the mine and should not be used when describing processing facilities. Mineral Resource estimates because they imply technical o Production/Operational Phase: feasibility and economic viability. Includes mining and processing of ore, resulting in a product for sale. Important Notes:  Mine Design Principles: o Overbreak (breaking rock outside of planned boundaries) should be o Mine design is a complex process avoided. involving interrelated tasks. o A free face is necessary for effective o Modeling techniques, including blasting, and the distance between a graphical, physical, and hole and the free face is called the mathematical modeling, are used to burden while the distance between evaluate different design methods. adjacent holes in the same row is o Optimization is important in each called spacing. stage of the mine design process. o Timing of detonations is important Factors to Consider: for fragmentation and to avoid ground vibrations. o Topography: Maps, aerial and land surveys are used to establish control o Controlled blasting techniques are stations and contours. used to minimize fracturing of rock beyond the designed boundaries, o Climatic Conditions: Includes including: temperature, rainfall, wind, and humidity. ▪ Presplitting: A row of holes is loaded with small charges o Infrastructure: Includes access and shot before the main roads, power supply, and water production shot to minimize sources. overbreak. o Government Considerations: ▪ Line drilling, smooth Includes political climate, mining blasting and cushion laws and restrictions. blasting are also mentioned o Economic Climate: Includes labor as controlled blasting availability, wage scales, taxes, and techniques. cost of goods and services. o Blast Design Parameters: o Waste Dump Location: Considers ▪ Burden: The distance haul distance and potential for between the blasthole and leaching. the free face. o Accessibility: Includes ▪ Spacing: Distance between transportation and communication adjacent blastholes. means. ▪ Bench Height: Height of the Mine Life and Production Capacity: working level. o Determining optimum production ▪ Powder Factor: The amount capacity and mine life is important of explosive used per volume for feasibility. of rock. o Net Present Value (NPV) is a ▪ Stemming: Material used to preferred method for evaluating contain explosive energy mining projects. within a blasthole. A good o Factors that influence total fixed and first approximation for operating costs include haulage, stemming column height is geomechanical features, diggability, 0.7 x burden. and slope stability. Mine Surveying o The optimization factor is used to o Mine plans must be maintained to maximize project NPV based on ore comply with regulations and for tonnage-grade distribution and safety. economic parameters. o Purposes include ensuring III. Mining Operations compliance with mining title Drill and Blast arrangements, maintaining a geographic database, and providing o Objectives include excavating control for mining excavations. planned rock volumes, achieving desired fragmentation and avoiding scattering broken rock.  o Mine plans include surface, I. Surface Mine Development underground, assay, geological and Introduction: Surface mine development ventilation plans. involves open pit mining for thick, steeply o Modern surveying techniques use dipping deposits and strip mining for thin, GPS, total stations, and digital shallow, flat-lying seams. Design requires modeling. balancing geometry, ore and waste characteristics, equipment, and economics. Ventilation The strategy varies based on the time o Planning involves determining the period of extraction and flexibility volume of air required and how to requirements. supply it. Open Pit Planning and Design: o Implementation includes designing o An open pit mine is an excavation airways and selecting equipment. open to the surface for the duration o Measurement and reporting involve of the mine's life, where ore is monitoring air quality and ventilation extracted. It often involves relocating equipment. large amounts of waste rock. IV. Geological Considerations o The main goal is to exploit the mineral deposit at the lowest cost, Geological Structures: maximizing profits. o Strike: An imaginary line on a rock o Open pit design involves devising surface where all points are of equal schemes, evaluating them, and elevation. selecting an optimum plan. Factors o Dip: An imaginary line on the such as ore body geometry, ore downslope surface of a rock distribution, topography, and formation. allowable slope affect the final design. o Unconformities: Can be used to mark geologic time boundaries. o Exploration data is crucial for decisions about pit size, layout, Structural Geology: production rate, and mineral processing. o Faults, bedding, joints, foliation and dykes are some of the structural o Geotechnical and geohydrologic geological features that affect mine investigations are important for mine stability. planning. Core samples should be oriented, logged, photographed, and Pit Wall Stability: sampled for materials testing. o Stability is influenced by structural Geologic data should be presented geology, groundwater, rock mass graphically to show property classification, geometry, alteration, variations. stress conditions, weathering, and o A block model is a representation of blasting. the ore body, aiding mine planners in o Numerical modeling (e.g. FLAC3D) selecting extraction methods. Bench is used to predict the effects of plans are prepared and combined to stress changes around the pit wall. form the overall block plan. V. Other Important Concepts o Stripping ratio is the amount of waste removed to uncover one unit Competent Person: A qualified of ore. The overall stripping ratio is professional who is responsible for the total waste volume to the total preparing and signing off on reports about ore volume. Exploration Results, Mineral Resources and Ore Reserves. o Feasibility studies determine how to mine and process an ore body to Transparency, Materiality and maximize net present value (NPV). Competence: These are the main principles Mine planning is dependent on the governing the application of the Philippine interaction of factors that maximize Mineral Reporting Code (PMRC). NPV. Modifying Factors: Mining, metallurgical, o Ore reserve analysis is the first step, economic, marketing, legal, environmental, including physical and financial social and governmental considerations.  parameters. A tonnage factor (TF) sufficient fragmentation for efficient converts rock volume to tonnage. bucket loading. Metallurgical flowsheets and design o The "maximum usefulness concept" criteria are developed. Breakeven can be used for preliminary selection analysis establishes a cutoff grade of stripping machines: MUF = dipper for ore. or bucket capacity × reach of the o Production scheduling uses machine. guidelines such as minimizing o Final machine selection depends on preproduction costs, ensuring bucket size, dumping radius, and adequate working room, smoothing dumping height, considering cost- stripping ratios, timely exposure of effectiveness. ore, reclamation, and maximizing production. o Continuous excavators (like bucket wheel excavators or BWEs) have Strip Mine Planning and Design: high output capabilities. o Planning requires consideration of o Mobile equipment such as tractor- many variables with complex scrapers are used for material interrelationships. handling. Scraper production o The planning process is depends on heaped capacity, interdisciplinary, requiring input from fillability, swell factor, and cycle time. various backgrounds. Design and Layout of Haul Roads: o Major steps in surface mine o Haul roads facilitate efficient and development include: (1) property safe transport. acquisition; (2) exploration; (3) feasibility studies; (4) mine planning; o Design factors include gradient, (5) detailed engineering; (6) width, curves, intersections, and permitting; (7) construction; (8) mine sight distance. operation; (9) reclamation; (10) closure. This can take up to 10 o Approach gradients should be as flat years. as possible. Adequate road signs are necessary. o Reserve estimation and geologic models are a major part of the II. Mechanical Extraction Methods planning process. The iso-line Operational Patterns: Material removal method involves constructing lines of occurs in sequential pushbacks, where one equal values for overburden and or more pushbacks constitute a phase or coal thickness. intermediate plan. o Economic stripping ratio is Mine Planning: The Mine Planning determined by setting a minimum Department defines cuts to meet production acceptable profit per ton of coal budgets, using computer models to recovered. determine if the material is ore or waste. Selection and Sizing of Excavating Product Control: Blasthole cuttings are Equipment: sampled, and if the area is in a projected o Loading shovels, draglines, cyclic ore zone, all samples are assayed. Each stripping machines, continuous mining block is identified with survey stakes excavators, and mobile equipment and flagging to distinguish between ore and are used in surface mining. waste. o Shovel cycle times are affected by Case Studies: The sources include digging conditions, swing angle, and descriptions of various mine sites, each with operator skill. its own unique characteristics. These include: o Draglines have good deep-digging characteristics and can operate from o Gold Quarry, which uses a computer any horizon. system to define ore, leach, and waste zones. o Large single-bucket stripping machines include walking draglines, o Colowyo Coal Company, which stripping shovels, and bucket wheel employs cast blasting methods and excavators. Blasting must result in reclamation practices.  Trapper Mine, which uses draglines for Remote operations require high productivity overburden removal and maintenance and may necessitate ore selectivity. programs. V. Auxiliary and Support Developments Big Brown mine which uses a box cut along Electrical Power Systems: These are a sub-crop for initial mining operations widely used due to their flexibility and Syncrude mine which is an oilsand mine reduced maintenance but costs are a major that uses draglines. component of operating costs. Frederick Quarry, which produces limestone Microcomputers: These influence nearly for construction materials. every aspect of surface mining. Friendsville Quarry, a dimension stone Artificial Intelligence (AI): AI extends the operation that produces marble. range of problems that can be solved with computers. Martin County Coal Corp. which extracts horizontal coal seams. Radiowave techniques: Radiowaves are used for communication and data Winifrede Seam which is an auger mining transmission. operation. Run-of-mine Rock Conveying: Conveyor III. Aqueous Extraction Methods systems may be used for blasted rock Placer Mining: Placers are low-grade without crushing, employing crib and cable deposits requiring high throughput of designs. materials. Exploration must be thorough to VI. Future Concepts determine the operating environment. Blasting Research: Focus on improving Hydraulic Mining: This method may use rock mass quality, fragmentation, burden pumps, eductors or hydraulic elevators for movement, and computer modeling for lifting slurry. predicting blast effects. Solution Mining: Continuous Excavators: Modifications for o Involves applying a lixiviant to ore to BWEs with driven precutters to address dissolve valuable minerals. abrasion. o Careful distribution of solution on the heap or dump surface is required. I. Mine Planning and Design o The application rate is the leach Introduction: Underground mine planning solution volumetric flow rate divided is unique because the infrastructure by the surface area. Surface advances into varying conditions. The goal acceptance rate is the maximum is an integrated system for mineral application rate without ponding. extraction and preparation at minimum cost, In Situ Techniques within social, legal, and regulatory limits. o Involves the use of wells to access Design Phases: Mine design generally has ore bodies and to introduce a three phases: conceptual, preliminary, and leaching solution, which is then final; the initial design is key. Errors in extracted for mineral recovery. geology, layout, or facility siting can lead to operational problems and economic losses o In-situ leaching is used to extract throughout the life of the mine. metals including copper and uranium. Planning Steps: The planning process includes: (1) baseline assessment, (2) o Frasch sulfur mining uses hot water reserve determination, (3) premine to melt and extract sulfur. planning, and (4) subsystem design. IV. Comparison of Methods Baseline Assessment: This is a review of Each mining operation is unique, with the all information, including geographic, prime objective being to maximize the return geologic, environmental, technical, and on investment. economic aspects. Geographic location influences economics and mining methods. Factors influencing mining method selection include: deposit characteristics, topography, Geologic Factors: A mine plan must be infrastructure, and environmental based on a sound mineral inventory. regulations. Geologic models are interpretations of  limited data, so new tests and drilling can encumbered space, and full-spectrum change the model and interpretation. practice. Techniques such as geophysical logging Equipment Classification: Equipment is and core photography are useful to obtain classified by its degree of activity (mobile quantitative data. vs. fixed-base) and objective of activity Reserve Determination: Key (excavating vs. bulk handling). characteristics of a reserve include depth, Production Analyses: Equipment with long inclination, geometry, and rock properties. A cycle times uses a tabular duty cycle mineral deposit is only considered a reserve approach, while short cycle times are when it can be profitably mined. Reserve typically found in tables. criteria are also a function of market demand and mining technology. Geometry of Design: Static design geometry of mining equipment must be Data Presentation: Reserve data is considered for understanding its effect on presented in a matrix indicating the certainty performance. of ore existence and economic recovery viability. Face Preparation: Cutting machines are used for face preparation; face drilling is Feasibility Study: A feasibility study also required. assesses the potential viability and minability of a project. It is important to Analytical Steps: A flow chart is used to evaluate the sensitivity of results to changes analyze equipment selection, involving in critical assumptions. Accurate cost problem statement, conditions, guidelines, forecasts need a life-of-mine plan, including equipment types, activities, space, design, reclamation costs. sizing, limits, performance, policy checks, and costs. Data Collection: From the beginning of the planning process, exploration permits are Problem Statement: Problem formulation needed to collect additional information to should be clear; it may involve evaluating formulate the plan. There is never enough existing equipment or selecting new information on a deposit to fulfill all design equipment. requirements. Analysis: Analysis considers conditions, Surface Facilities: The size and location of activities, and equipment, with suitability surface facilities depend on the productive tests. capacity of the operation and the reserve size. Considerations include access, Conditions: Conditions include geography, extraction, removal, storage, transportation, geology, and material properties. workforce, and operational needs. Suitability Analyses: Guidelines for The Mine Planning Process: This process equipment selection come from texts, is complex and requires knowledge of handbooks, company files, and experience, geology, laws, regulations, equipment, and are matched to conditions. mechanical/electrical/civil engineering, and Equipment Type: Once the equipment type mining engineering. Plans are developed is established, functional aspects and based on available data, and are subject to variants are described. change as new information becomes available. Performance Rate: A systematic procedure involving conditions, activities, and II. Equipment Selection and Sizing equipment characteristics is used to Importance: Equipment selection is a major determine performance rates. activity that follows the decision to mine and III. Mine Plant Layout the selection of a mining method. Analyses are conducted after layout and sequencing Definition: Mine plant layout is the process but before scheduling. of configuring all mine facilities, such as structures, machinery, pipelines, power Organizing Principles: Understanding lines, equipment, roads, and rails. unique conditions is essential for equipment selection, especially the concept of Mine Size: Large, long-lived mines require "encumbered space". Engineering detailed engineering and large layout areas, dimensions provide a checklist. while smaller mines may have portable surface plants. Mining's Uniqueness: Mining is unique due to its total systems concern, Historical Context: Early mine plant descriptions are found in De Re Metallica  (1556) which focused on pumping, advancing and lining erection in good rock ventilation, and processing. conditions with limited water inflow. Plant Layout: Mine plant layout is divided Shaft Bottom Depth: The depth of the shaft into surface, shaft, and underground areas. bottom must allow for the required hoisting equipment. General Analysis Approach: A general analysis approach is required to design a Shaft Sinking: Various methods include mine plant layout since no specific set of long lifts, shotcrete lining, and timber lining. design parameters exists. Timber Lining: Round or square timber is Plant Layout Methodology: This puts used for timber lining and should be treated guidelines into practice to bring mine plant to avoid decay. concepts to fruition. Grouting Systems: Grouting is used to Basic Plan: A basic plan balances company seal the rock mass around the shaft, goals with cost, time, and technical preventing water inflow. constraints. Freezing Method: The freezing method can Initial Layout: Initial efforts involve a be used to create a frozen rock cylinder "thumbnail" sketch of expected operations around the shaft in unstable ground. at potential access sites, considering Slope Development: Slopes can be mineral production and processing. developed with conventional drill-and-blast Design and Cost Estimates: From the methods or with roadheaders. thumbnail sketch, engineers develop V. Hoisting Systems specifications for each subsystem and estimate construction costs. Access Types: Mine access includes vertical shafts using hoists and cable Drawings: Mine plant layouts are generally conveyances, or horizontal/inclined placed on schematics, plats, or layouts, openings using rail, trucks, conveyors, or which orient the items to an exact scaling cable-operated conveyances. and position. System Components: A shaft hoisting IV. Shaft Design and Construction system includes the hoist, conveyance, Technical Data: Shaft design requires a rope, shaft, and headframe. project outline, including shaft purpose, Design Parameters: Design parameters for location, characteristics, and capacity. evaluating access systems include the Excavation Design: This involves gathering purpose of the opening, duty requirements, geological data, determining shaft diameter, and size of the opening. selecting a sinking technology, and Rope Use: Steel ropes have different describing shaft linings. constructions for hoisting, balancing, and Geologic Information: Reliable geologic guiding. information from core drilling is needed for Shaft Purpose: Shafts can be used for shaft design. production, service, ventilation, exploration, Shaft Linings: Linings support equipment or escape. and walls, with concrete being a common Shaft Configuration: Common shaft material. configurations are circular, rectangular, and Lining Thickness: The thickness of the elliptical. shaft lining is calculated based on shaft Hoist Design: Design involves determining radius, concrete stress, work conditions, hoisting speed, acceleration, deceleration, and outside pressure. and maximum speed. Shaft Collar: The shaft collar is the upper Rope Construction: Factors in rope part of the shaft, anchored in competent construction include the wire, strands, rock. cores, and lay. Shaft Insets: Insets for hoisting shafts Rope Strands: Common strand types depend on the width and number of skips include round, triangular, oval, and flat. and cages. Rope Cores: The core takes the internal Conventional Methods: Conventional compressive stresses of the rope. methods involve repeated cycles of face  Rope Sizing: Rope sizing involves Blasting: Blasting characteristics of the tabulating conditions, calculating loads, and rock is assessed for selecting hole size and checking the safety factor. drilling system. Headframe: Headframes can be permanent Blocking: The process of securing two or temporary, and should accommodate wedges near the bottom of the blasthole. rock disposal. Mass Blasting: The mass blast involves VI. Room and Pillar Mining shooting all the remaining holes in the stope. Stress Distribution: Solutions for stress distribution are given for square and Mucking: Selective mucking is done to rectangular openings. draw down broken ore. Pillar Design: Pillar stress can be IX. Cut and Fill Mining estimated as a proportion of pillar stress Overhand Cut and Fill: Horizontal cuts are computed from tributary area theory. mined, with excavated ore falling onto the Support Design: Bolt tension forces can be backfill. calculated to support the roof. Timbering: Timber is framed together to Reinforcement Factor: A reinforcement form rectangular sets for support. factor evaluates the interbed friction effect Development: Development includes due to bolting. primary development (main access) and Span: A hard and intact rock is not cavable secondary development (stope preparation). and requires a span of over 20 times the Cost Estimation: Spreadsheet models are excavated thickness. used to estimate exploitation costs. Panel Layout: Room and pillar mining X. Sublevel Caving occurs in regular rectangular sections or panels. Extraction Ellipsoid: The existence of the extraction ellipsoid can be demonstrated Productivity: Productivity of noncoal room using three-dimensional models. and pillar mines are dependent on the number of unit operations. Gravity Flow: Gravity flow can be interrupted due to settlement and Systems Analysis: The room and pillar compaction of blasted ore. method is suitable for simulation modeling. Testing: In situ testing is used with VII. Stope and Pillar Mining radioactive markers to determine gravity Stope Development: Mine development flow. usually begins with a shaft in the footwall, Extraction Ellipsoids Shapes: The shape with crosscuts and haulage levels of the extraction ellipsoid can be rounded or subdividing the ore body. angular. Sublevel Development: Access raises are Practical Design: The width and thickness used to subdivide the ore body into blocks of the extraction ellipsoid must be for stoping, with sublevels driven through determined to satisfy parameters of gravity the proposed stope block. flow. Sill Pillar Thickness: This depends on the Dilution: Total dilution development is ore handling system, and is generally defined at the beginning of the process. between 30 and 70 ft. Geometry: Sublevel caving geometry is VIII. Vertical Crater Retreat (VCR) Mining determined by sublevel height and spacing General Methodology: VCR mining is of sublevel drifts. appropriate for ore bodies that can flow XI. Block Caving down to drawpoints under the influence of gravity. Geology and Rock Mechanics: A geologic and rock mechanics study is made before a Stope Design: Stope components are decision is made to use block caving. modified as new information becomes apparent. Productive Capacity: Block caving is suitable for high daily production. Equipment: LHDs, diesel jumbos, jacklegs and track muckers are all used in Draw Rate: The daily rate of draw depends development. on how fast the ore caves.  Draw Area: Draw area can be approximated based on median fragment size. Drawpoint Spacing: Drawpoint spacing is determined by the rock characteristics of the ore. Drawpoint Dimensions: Drawpoint dimensions are determined by equipment and ore characteristics. XII. Method Selection Flexibility: Proper method selection must allow maximum flexibility to adapt to unexpected conditions. Goals: Goals must be aggressive yet achievable, within constraints of tonnage, grade, reserve confidence, and potential for expansion. Mine Life Plan: A mine life plan looks at scheduling for the entire project and evaluates all phases. Continuing Modification: Ongoing examination and modification of previously established components are needed. Operations Plan Development: An operations plan integrates mine plan projections, production forecasts, ventilation, water supply, haulage, power, and equipment.