16510015049500 Department of Mining Engineering and Mine Surveying
Module: Mining Engineering Practice 1B
Learning Unit: 3
Student number: 201592553
Initials: K Surname: MOLOTO
Assessor: (Mr, T, Mmola)
Portfolio instructions (as given by assessor): You are required to compile a portfolio that summarises what you have learnt during the activities associated with learning units 3. You are also required to reflect on each section of work and consider how this will be applicable to you in your future career as a mining engineering technologist.
Learning outcomes and assessment criteria (To be completed by student).
No Outcome Assessment criteria
1 Awareness of the basic activities in the mining production cycle.
Be conversant with production mining terminology as used in industry. Present a coherent mining production cycle and describe the essence of each part. Name the roles, tasks, and responsibilities of production mining personnel. Name the production equipment and material used in mines.
2 Basic knowledge of underground mining methods.
Be conversant with underground mining terminology as used in industry. Describe how a mineral deposit is exploited with under-ground mining methods.
Specific Outcome 1. Basic Activities in the Mining Production Cycle and Production Mining Terminology as Used in Industry.
Basic Activities in the Mining Cycle
Prospecting (Mineral Deposit): the stage where ore or other valuable minerals are searched by:
Prospecting methods: direct (physical geologic) and indirect (geophysical and geochemical).
Find a suitable place (maps, literature, and old mines).
Air: aerial photography, airborne geophysics and satellite.
Surface: ground geophysics and geology.
Spot an outlier, analyse and evaluate.
Exploration (ore body): Examine and evaluate the extent and the value of ore by:
Taking samples (drilling or excavation), examine and test them.
Estimate tonnage and grade.
Estimate the value of ore and decide on whether to develop or abandon.
Development (prospect): opening up ore deposit for production.
Obtain mining rights (purchase or lease).
file environmental impact statement, technology assessment and permit.
build access roads for transport system.
Designate the site of surface plant and construct facilities.
Ore excavation (strip or sink shaft).
Exploitation (mine): large scale production of ore.
factors in choice of method: geologic, geographic, economic, environmental and societal safety.
Types of mining methods: surface (open pit, open cast, etc) and underground (room and pillar, block caving, etc).
Oversee costs and economic compensation.
Reclamation (real estate): restoration of site.
Reclamation of waste and tailings dumps.
Monitoring of discharge.
Roles, Tasks, and Responsibilities of Mining Production Personnel.
Determine materials and move containers commensurate to given instructions.
Use fork life truck to load and unload materials.
Move materials from storage or work sites to an appointed area.
Operate industrial truck/electric hoist to assist in loading materials and products.
Set up machinery and make sure that all production material is available.
Operate and oversee equipment and restock materials as required.
Determine and report faults to appropriate parties.
Maintain equipment and assigned production area cleanliness.
Follow company policies and procedures.
Perform all production related tasks and activities.
Maintain positive work relation with customers, vendors, co-workers and management.
Maintain production equipment and communicate future requisition to plant manager in writing.
Perform given task and comply with quality systems requirements.
Maintain proper stock levels to ensure shipments are complete.
Promote safety and implement company policies always.
Production Equipment and Materials Used in Mines
Mining Drills: used in creating holes descending underground. For instance, if miners are required to work underground, drills will be used in creating large enough holes to be used as a passageway for miners.
Blasting Tools: used to break down and fracture rocks by use of explosives to separate the valuable product from the waste material. Blasting is also used to remove pockets of unwanted material that prevents mining machines and personnel access to the seam containing valuable materials.
Earth Movers: used regularly to carry loose soil and rock-based material from one location to another. They are also used for digging, pushing and transporting the rock-based materials.
Crushing Equipment: used to break down the hard rock matter or gravel to fine particles and manageable size for transportation.
Feeding, Conveying, and Online Element Analysis Equipment: once the excavator transporter brings the raw material to the crusher for processing, the feeding device feeds the material into the crusher and in return the material is screened and all oversized material is recirculated back to the crusher to ensure correct size fraction is obtained. They are necessary to the mining industry to move and control material flow within a mining and processing operation, to facilitate efficient operation of equipment and determine operating rates and yields.
Specific Outcome 2. Underground mining methods.
Underground mining methods are divided into three classes on the basis of the extent of support required: unsupported, supported and caving.
Unsupported: used to extract mineral deposits that are roughly tabular and are generally associated with strong ore and surrounding ore. These methods are called unsupported because they do not use any artificial pillars to assist in the support of the openings. However, generous amounts of roof bolting and localized support measures are often used.
Room and pillar mining: the most common unsupported method, used primarily for flat-lying seams or bedded deposits like coal, trona, limestone, and salt. Support of the roof is provided by natural pillars of the mineral that are left standing in a systematic pattern.
Stope and pillar mining: a similar method used in non-coal mines where thicker, more irregular ore bodies occur. The pillars are spaced randomly and located in low-grade ore so that the high-grade ore can be extracted.
Shrinkage stoping: is characterized by the mining advance being upward, with horizontal slices of ore being blasted along the length of the stope. A portion of the broken ore is allowed to pile up in the stope to provide a working foundation for the miners and is thereafter removed from the stope through chutes. Shrinkage stoping is more suitable than sublevel stoping for stronger ore and weaker wall rock.
Sublevel stoping: differs from shrinkage stoping by providing sublevels from which vertical slices are blasted. In this manner, the stope is mined horizontally from one end to the other.
Supported: often used in mines with weak rock structure.
Cut and fill: most common of these methods and is used primarily in steeply dipping metal deposits. This method is practiced both in the upward and in the downward directions. As each horizontal slice is taken, the voids are filled with a variety of fill types to support the walls. The fill can be rock waste, tailings, cemented tailings, or other suitable materials. Cut and fill mining is one of the more popular methods used for vein deposits and has recently grown in use.
Square set stoping: involves backfilling mine voids. However, it relies mainly on timber sets to support the walls during mining.
Stull stoping: uses timber or rock bolts in tabular, pitching ore bodies. It is one of the methods that can be applied to ore bodies that have dips between 10° and 45°. It often uses artificial pillars of waste to support the roof.
Vertical Crater Retreat (VCR): can be either supported or unsupported method based on the carter blasting technique in which powerful explosive charges are placed in large-diameter holes and fire. Part of the blasted ore remains in the stope over the production cycle, serving as temporary support for the stope walls.
Caving: methods of mining are diverse and inconstant and involve caving the ore and/or the overlying rock. Subsidence of the surface normally occurs afterward.
Longwall mining: this method is specifically suited to horizontal seams, usually coal, at some depth. In this method, a face of considerable length (a long face or wall) is maintained, and as the mining progress, the overlying strata are caved, therefore promoting the breakage of the coal itself.
Sublevel caving: employed for a dipping tabular or massive deposit. As mining progress downward, each new level is caved in into the mine openings, with the ore materials being recovered while the rock remains behind.
Block caving: a large-scale or bulk mining method that is highly productive, low in cost, and used primarily on massive deposits that must be mined underground. It is most applicable to weak or moderately strong ore bodies that readily break up when caved. Both block caving and longwall mining are widely used because of their high productivity.