Elements Of Mining (MNC 200) Lecture Notes PDF

Elements of Mining (MNC 200) Monsoon Semester – 2024-25 Lecture: 10-11 Prof. Anindya Sinha Department of Mining Engineering, IIT (ISM), Dhanbad 1  ELEMENTS OF MINING (MNC 200): Sy...

Elements of Mining (MNC 200) Monsoon Semester – 2024-25 Lecture: 10-11 Prof. Anindya Sinha Department of Mining Engineering, IIT (ISM), Dhanbad 1  ELEMENTS OF MINING (MNC 200): Syllabus  Mining :  Definition and economic importance;  Mine – definition, different types and classification; Mine life cycle;  Exploratory Drilling;  Mineral deposit – different types and their classification; Mineral resources of India;  Opening-up of Deposits:  Choice of mode of entry - adit, shaft, incline, decline and combined mode, their applicability, number and disposition.  Box cut - types and location  Vertical/Inclined Shafts, Inclines/Declines:  Location, shape, size,  Organization of shaft sinking, sinking methods,  Construction of shaft collar, shaft inset, shaft fittings.  Methods of incline/ decline drivage.  Overview of underground (UG) mining:  Different coal mining methods and their applicability & limitations;  Different metal mining methods and their applicability & limitations;  Basic concepts of transportation, ventilation, illumination and support in UG mines.  Overview of surface/ opencast (OC) mining:  Types of surface mines, applicability & limitations, 2  Unit operations and equipment selection, Pit geometry and layout.  Opening-up of a Deposit  Choice of mode of entry: Adit, shaft, incline, decline and combined mode, their applicability, number and disposition.  Box cut - types and location (Note: Will be taken up with Surface Mining lectures.) 3  Definition of a Mine: As per Mines act 1952  Mine means any excavation where any operation for the purpose of searching for or for obtaining minerals has been or is being carried on and includes i. All borings, bore holes, oil wells and accessory crude conditioning plants, including the pipe conveying mineral oil within the oilfields; ii. All shafts, in or adjacent to and belonging to a mine, whether in the course of being sunk or not; iii. All levels and inclined planes in course of being driven; iv. All conveyors or aerial ropeways provided for the bringing into or removal from a mine of minerals or other articles or for the removal of refuse therefrom; v. All adits, levels, planes, machinery works, railways, tramways and sidings in or adjacent to and belonging to a mine; vi. All protective works being carried out in or adjacent to a mine; 4  Definition of a Mine: As per Mines act 1952 vii. All workshop and store situated within the precincts of a mine and the same management and used primarily for the purposes connected with that mine or a number of mines under the same management; viii. All power stations, transformer sub-stations converter stations : rectifier stations and accumulator storage stations for supplying electricity solely or mainly for the purpose of working the mine or a number of mines under the same management; ix. Any premises for the time being used for depositing sand or other material for use in a mine or for depositing refuse from a mine or in which any operations in connection with such and refuse or other material is being carried on, being premises exclusively occupied by the owner of the mine; x. Any premises in or adjacent to and belonging to a mine or which any process ancillary to the getting, dressing or operation for sale of minerals or of coke is being carried on; xi. all opencast workings which means a quarry, that is to say an excavation where any operation for the purpose of searching for or obtaining minerals has been or is being carried on, not being a shaft or an excavation which extends below 5 superjacent ground;  Surface Mining Vs. Underground Mining  After ascertaining the presence, extent and economics of the mineral deposit it is to be decided whether it will be worked by surface mining or by underground mining.  Shallow deposits are extracted by surface mining or opencast mining methods. In this method, the overburden (i.e. the material lying over the deposit) is removed to expose the mineral, which is then extracted.  If the depth of the deposit is such that removal of the overburden makes surface mining uneconomical, underground mining methods have to be used. 6  Mine Development  Mine development essentially involves driving primary and secondary openings so as to reach the mineralized zone and make it amenable by suitable method of extraction. It may be noted that the development layout depends on the method of extraction. A considerable length of development drivage is required before a deposit is finally extracted.  Primary Development: The primary development drivages are done primarily to provide an access to the orebody from the surface.  This serves:  To provide access to the mineral deposit,  To provide transport for men, material and the mineral,  To carry air for the ventilation of the underground workings for men and machines,  To accommodate pipes and cables leading to the underground workings for transmission of compressed air, power, water and backfilling materials, like sand etc.  Secondary Development: Secondary development openings can be driven within the deposit, as in practice in flat - lying coal seams (e.g., drifts, entries, crosscuts), or outside the deposit, as is generally practiced in three – dimensional ore bodies in metal mines (e.g., adits, tunnels, drifts). These supplements the main entries and serves the same purpose.  Mine Entries: Following Mine Entries are normally excavated for making access to the ore body: (a) Vertical shaft, (b) Inclined Shaft, (c) Adit, (d) Slope/ Incline/ Decline. 7  Major Steps/ Activities for Opening of a New Mine 1. Allocation of a Coal/ Lignite Blocks (Part A & B in Schedule I of the Mines and Minerals (development and Regulation) (MMDR) Amendment Act 2023) by Ministry of Coal (MoC), Govt. of India (GoI) and Mineral Blocks (listed in Schedule II) by the respective State Govt. 2. Regional/ detailed exploration of the allocated block with drilling of boreholes & logging by the allottee, if not done earlier. 3. Preparation of Geological Report (GR) incorporating land profile, mineral structure, geological features, physico-mechanical properties of mineral and host rocks, grades of mineral at every stage and other geological details. 4. Preparation and submission for approval of Mining Plan (inclusive of Mine Closure Plan) from Ministry of Coal, GoI/ Indian Bureau of Mines (IBM). 5. Confirmation of Mining Method and equipment (as approved in the Mining Plan referred above) and procurement of initial equipment. 6. Arrangement of Financing - Equity, Debt, Joint venture, consortium etc. so that cost of capital is minimal. 8  Major Steps/ Activities for Opening of a New Mine 7. Land Acquisition: o Tenancy Land acquisition under Right To Fair Compensation And Transparency In Land Acquisition, Rehabilitation And Resettlement Act, 2013 Act (RFCTLARR) (through State Govt.) by project proponent other than Govt. PSUs. o Govt. Companies (Central Govt. PSUs) are allowed to acquire land under Coal Bearing Area (Acquisition and Development) (CBA) Act, 1957 o Forest Land Acquisition (if involved) under Forest Conservation Act 1980 requires two stages namely Stage - I & Stage – II 8. Obtaining mineral right: Mineral right/ Mining lease from state govt. under MMDR Act, 2023 (not required if acquisition done by CBA Act 1957). 9. Filing of Environment Impact Assessment (EIA) & approval of Environment Management Plan (EMP) under Ministry of Environment, Forest & Climate Control (MoEF&CC) - to be made concurrent with Sl. No. 7 above. 9  Major Steps/ Activities for Opening of a New Mine i. As per EIA Notification,2006 (based on Environment Protection Act, 1986); Submission of Form 1 on-line in Parivesh Portal of MoEF&CC ; ii. Application for NoC for abstraction of water from Central Ground Water Authority (CGWA) - to get it secured before grant of EC ( no. iv as below); iii. Issuance of Terms of Reference (ToR) from MoEF&CC; iv. Stage - I FC to be secured from MoEF&CC before submission of final EIA/EMP for grant of EC, if forest land is involved; v. As per EIA Notification, 2006 (EP Act 1986) - Submission of final Environmental Management Plan (EMP) after completion of Public Hearing and compliance of conditions stipulated in ToR to MoEF&CC on Parivesh Portal, for grant of Environmental Clearance(EC). 10  Major Steps/ Activities for Opening of a New Mine 10. Consent to Establish (CTE) under Air (Prevention & Control of Pollution Act, 1981 (amended in 1987) & Water (Prevention & Control of Pollution Act, 1974 (amended in 1988) from respective State Pollution Control Board (SPCB). 11. Consent to Operate (CTO) under Air (Prevention & Control of Pollution Act, 1981 (amended in 1987) & Water (Prevention & Control of Pollution Act, 1974 (amended in 1988) from respective State Pollution Control Board. 12. Signing of Tripartite Agreement with Coal Controller Organization (CCO)/ Indian Bureau of Mines (IBM), Project Proponent & Escrow Agent; Opening of Escrow Account. Securing Mine Opening Permission from CCO under Ministry of Coal, GoI for coal mines/ from IBM under Ministry of Mines, GoI for Non Coal Mines. 13. Obtaining other statutory permission from Directorate General of Mines Safety (DGMS), Petroleum and Explosives Safety Organization (PESO). 14. Securing Stage-II FC in case of involvement of forest land and subsequently physical possession of Forest land. 15. Access from main road, laying of railway track, HT transmission line, communication lines/ mobile towers etc. 16. Access from surface i.e. access trench in case of surface mines for the purpose of transportation of mineral & overburden, and shaft sinking/ drivage 11 of inclines/ adits for UG mines for transportation of men/ mineral/ material.  Major Steps/ Activities for Opening of a New Mine 17. Construction of magazines (for storage of explosives), Substations (for power Supply), telecommunication infrastructure, Machinery erection yard, Workshops etc. 18. Sand Stowing Plant (for UG sand stowing)(if required), Sand Preparation Plant (if required) etc. 19. Construction of Industrial buildings (offices, canteen, rest room, workshops etc.) and welfare buildings (housing, water supply system, medical facilities etc.); 20. Construction of Mineral Processing Plant/ Coal Handling Plant/ SILO/ Rapid Loading System/ Railway Siding/ Linking with Trunk/ Main Line & provision of Stock Piling; 21. Procurement of mining equipment for development & exploitation as well support equipment; 22. Recruitment & training of work force; 23. Other development works concurrently or before commissioning of the project. 12  Mine Entries  Broadly there are four approaches to gain access to an orebody, namely, adits, incline shafts, vertical shafts, and declines or ramps.  Depending upon the nature of the deposit and degree of its exploitation, the mine engineers/ planners need to do due diligence in selection of mine entries in a proposed mine area. It is more complex while investigating the viability of shallower deposits.  Each deposit has it own characteristics and requirements and requires an accurate evaluation of all factors that may affect the mine design to access the orebody. The selection of proper size, configuration, arrangement and type of opening/ mine entries required to develop a new underground orebody is often an engineering challenge. The basic design parameters that should be considered are as follows: Lowest capital expenditure Lowest operating cost Safe and reliable operating system Flexible and efficient system Supports the mine planning Allows mechanization of mine 13 Provides faster access to the orebody to promote early cash flow.  Mine Entries  The design of a mine entry/access is an important aspect of the overall mine design. Each individual deposit needs a carefully review and thorough analysis.  The development of any of mine entries involves substantial capital expenditure – highest being in case of vertical shaft. The selection of decline or shaft access may not be straightforward as the economics of the access options change with depth and tonnage.  If all the design criteria are not considered in the initial phase of the project then the mine access can potentially become a bottleneck. For example, the opening must be of sufficient size to handle ventilation, planned equipment, envisaged output etc. Therefore, it is advisable to design any such mine entry with certain flexibility to cater to any unexpected change/ future requirement of the mine.  Once an entry is established for a mine, it may become impractical to increase production throughput due to the size of the shaft or decline. 14  Mode of Entries 15  Adits or Drifts Adits offer an entrance into an underground (UG) mine that is horizontal or near horizontal and provides access for personnel, material, rock, ventilation, and mine drainage. Adits are driven into a hill or mountain and are often developed when the deposit is located inside the mountain and above the adit. Adits are generally driven slightly inclined upward to allow self drainage of mine water out of the mine. Characteristics: Hilly terrain; Level drift from foot of hill to intersect the deposit; Outcrop above loading level; Sufficient space available at mouth of adit for surface infrastructure; Cheapest mode of entry; Can be equipped with locomotive haulage (cyclic) or conveyor (non-cyclic) for high Production capacity; Transportation of manpower is easier & faster. 16  Adits or Drifts 17  Slope/ Incline Characteristics of Slope / Incline:  Long life;  Excavation of normally rectangular cross section;  Suitable for shallow to medium depth deposit;  Quicker access to the deposit;  Cheaper drivage (per meter) at faster pace with early return on investment. However, as compared to shaft - longer drivage (resulting in higher resistance to ventilation), longer cable and pipeline etc.  In geologically disturbed area, maintenance of Incline is difficult and costly.  Transportation of manpower is easier and faster.  Trackless and noncyclic continuous mining is possible in straight slopes. High production capacity mine can be built up with conveyors installed at 16% (9.10) gradient;  In inclines, even trucks can be deployed at a gradient of 12 to 14% (6.80 to 80). 18  Decline A decline is essentially a system of ramps and crosscuts that connects the access points (points which must be accessed for drilling and blasting operations) and draw points (from which the ore is drawn) to the surface portal or to a breakout from existing mine infrastructure. Characteristics of Decline: Longer life; Excavation of normally rectangular cross section. Suitable for flat deposits at shallow depth; Low initial capital cost and operating cost, but slow return on capital; Longer haul distance for deeper deposits; Trackless mining with high hauling capacity is not possible; Transportation of manpower is easier but time taking; Water handling is a problem with declines; Length of cable for power supply is longer; In declines, trucks can be deployed for transportation of minerals at a gradient of 12 to 14% (6.80 to 80) (in metalliferous mines); Declines allow the movement of equipment from one level to another without need for disassembling, transporting, & reconstructing the equipment, which is often required in a vertical shaft system. Declines must provide adequate turning radius for the largest piece of equipment. Main Advantages of decline systems are the low cost of development, ease of access for equipment, and the short period to commencing mining operations. However, disadvantages included low vertical development rates, increased ventilation requirements due to larger length and the use of diesel equipment, & increase in labour to 19 support truck operation.  Vertical Shaft  Shafts are vertical excavations sunk in a position so as to access the orebody as effectively as possible, with the size of the shaft excavation generally being determined by the production and ventilation requirements. Depending on a variety of considerations, vertical shafts are typically sunk when orebodies extend deeper than 250 m to 500 m, as shafts then become more economic than a decline ramp system. Shafts are usually placed such that horizontal distances to the ore body are minimized. Shafts vary in shape and dimension, but are normally circular depending on geotechnical and environmental considerations.  The advantages of shafts are that they support moderately high production rates, and are efficient for the transportation of personnel, material, and rock. Disadvantages include the high initial capital expenditure, long lead time to production, and difficulty in transporting large equipment.  It is a vertically downward excavation of larger circular cross. It is sunk for:  Deeper flat deposits (700),  Moderate Production Capacity with skip because of cyclic vertical transportation,  Longer life,  Capital cost is higher with longer construction time,  Cheaper for deeper deposits when both capex and opex are considered. Operating cost is less,  Because of shorter drivage length there is less resistance to ventilation and can be equipped with shorter cable and pipeline,  High Skill requirement for drivage with limited availability,  Transportation of manpower is easier and faster, 20  Further Exploration is possible.  Vertical & Inclined Shafts  Vertical Shaft is a vertically downward excavation of circular cross-section suitable for skip winding. It is normally sunk for Deep flat deposits (700); Bad Natural Condition; Moderate Production Capacity because of cyclic vertical transportation; Long life.  Inclined Shaft characterises: Excavation of normally rectangular cross section with haulage tub combination or even with skips in steep shafts; Moderately inclined deposit (300 to 700); Moderate Production Capacity because of cyclic transportation on steep slope; Moderate mine life; Less horizontal development; Exploration is also possible during drivage. 21  Vertical Shaft Vs. inclined shaft  The main deciding factors are: (i) type of mineral deposit and (ii) depth of the deposit.  For coal or other flat-lying formations, generally the depth is the deciding factor. When an ore deposit lies at a depth not exceeding 300-400m, Inclines/slopes are usually driven.  But, at greater depths, Shafts are the usual choice.  If the ore-body is vertical or very steep, obviously Vertical Shaft is a natural choice. We can have the shaft in the ore body itself if the ore body is strong because shaft has to be a stable and long lasting. But this may lock up a lot of the mineral for the protection of the shaft.  For inclined deposits, the choice will depend upon the dip of the ore body. Vertical Shafts require cross-cuts to be driven to the ore body. As such, at a greater depth the total length of the cross-cuts increases as the depth of the shat increases. 22  Vertical Shaft Vs. inclined shaft  To minimize the aggregate length of the cross-cuts, an inclined shaft can be sunk in the footwall parallel to the ore body. Such a shaft has the advantage of short length of x-cuts, stable, quick access, less expenditure on the short x-cuts which may offset higher cost of drivage of inclined shaft  If the deposit has a uniform dip, the vertical shaft should intersect the deposit at half the ultimate depth of the mine so that the aggregate length of the X-cuts is the shortest. (Say 500 m is the ultimate depth – shaft should intersect the vein at 250 m depth). In this case the upper part of the shaft is in the hangwall but extraction of the ore body may damage the shaft. Because the shaft has to last till the full life of the mine. So, we have to keep a safe margin between the workings and the shaft or we have to adopt a suitable method of mining so that the shaft is not affected by the workings.  When the dip of the ore body is not uniform the inclined shaft can not be parallel to the orebody because this will reduce hoisting capacity and increase the cost of operation. For the most economical hoisting, inclined shafts should be straight. A few bends of slight curvature may not have serious effects but a shaft cannot afford to follow the deposit of irregular dip. 23  Location of Vertical or Inclined Shaft  For Choosing between a vertical and a inclined shaft, the overall economy has to be worked out.  Generally, inclined shafts are used for inclined ore bodies (300 to 700).  Beyond 700 (between 700 & 900) vertical shafts are more economical.  An inclined shaft is larger in length, hence costlier and requires more maintenance. The production capacity of a mine with inclined shaft is having 25% less than that with a vertical shaft of same cross section.  The latest trend is to sink vertical shafts for obvious advantages of efficient winding with optimal capex and opex. 24  Vertical Shafts vs. Slopes/ Inclines Important Parameters for a Mining Project: SN. Parameters Vertical Shaft Slopes/ Inclines 1. Time requirement for completion More Less 2. Capital cost More Less 3. Continuous transport of mineral Cyclic Continuous 4. Capacity of ore/ coal transport Moderate Large 5. Operational cost More Less 6. Resistance to ventilation Less More 7. Length of cable, pipeline Less More 8. Possibility of uncertainty impacted by Less More geological factors 9. Loss of coal in protective pillar Less More 10. Environmental problem More Less 25  Comparative Parameters 26  …Thank You… 27