MNG Quiz 4 Verified Exam Score A+ Guaranteed Distinction.

Secondary mining method to recover additional coal from under the highwall of a contour mine when the ultimate stripping ratio has been achieved in open cast operations. - correct answer Auger mining This method is used to recover deep deposits, that can easily be dissolved by a solvent. Typically, it would be too expensive to mine using underground methods. Water, acid and steam are common solvents. Examples of commodities include: uranium and sulfur - correct answer Solution mining (surface, aqueous) In this mining method, the ore is weak and cannot support its own weight. Typically the host rock is fairly strong. The ore is undercut and then as the broken ore is removed, the remainder of the orebody collapses into the void. This repeats and can break through to the surface. - correct answer Block Caving (underground, caving) In this mining method, the host rock is weak and cannot support its own weight, but the orebody is strong and massive . This type of mining starts at the top of the orebody and progresses downward in a safe sequence with the orebody being blasted and removed underneath. The cave will reach the surface. - correct answer sublevel caving (underground, caving) Method used for extracting dimension stone (like granite countertops, marble flooring, monuments, etc). Goal is to remove large slabs. Rock mass has high strength and competency. This term is used by many to describe any open pit operation in stone. Examples included Georgia marble and Vermont granite. - correct answer Quarrying (surface, mechanical) In this mining method, the ore is a horizontal tabular deposit such as coal. The material is sheared off in slices. Once the coal is removed the overlying strata caves into the void left by removing the coal. Trona is another commodity mined using this method. - correct answer longwall mining (underground, caving) Mining method used for near-surface deposits. A large pit is excavated and overburden is hauled away to a waste area. Benches are created to help increase the pit depth. A few examples of commodities mined by this method would include iron and diamonds. - correct answer Open pit mining (surface, mechanical) Used to recover weaker strength materials where the opening will not remain stable after ore is removed. Backfill is placed into the opening to support the ore above the slice of orebody removed. This method is expensive and only used for high value ores such as gold. - correct answer Cut and fill (underground, supported) This underwater recovery method uses a floating mining machine for recovery of loosely consolidated material. Sand and gravel are examples of commodities. - correct answer Dredging (Surface, aqueous) Used to recover steeply dipping orebodies in competent rock. Ore is removed as soon as it is mined. Important varients are: sublevel stoping and big hole stoping. Commodity examples include: iron, lead/zinc. - correct answer Open stopping (underground, unsupported) This secondary method recovers low percentages of metals remaining in the tailings from mineral processing plants. A solvent drips and percolates down through the heap and then recovered and processed. Gold and copper are commodities mined using this method. - correct answer Heap leaching (surface, aquesous) This method is used when host rock is reasonably competent and orebody is steeply dipping. Broken ore is left in place to support the walls of the stope until all of the broken ore is removed. An important varient of this method is known as vertical crater retreat (VCR) mining. Commodities mined by this method include iron and palladium. - correct answer Shrinkage stopping (underground, unsupported) What are the 6 most important factors to consider when deciding which mining type to use? [Be able to describe each factor and why] - correct answer 1) depth 2) surface features (especially for, but not limited to surface methods) 3) attitude, shape, and size (extent) 4) geotechnical characteristics of the orebody and the host rock 5) grade and uniformity 6) production requirements This method accounts for the vast majority of all underground mining in the US (and likely the world). It is used to recover bedded deposits that are horizontal or nearly horizontal when the orebod and the surrounding rock are reasonably competent. Other than pillars, little artificial support is required (mostly consists of bolts placed into the overlying strata to make a strong laminated beam) Commodities mined using this method: coal, lead, limestone, and salt - correct answer Room and Pillar mining (underground, unsupported) This method utilizes a high-pressure water cannon to dislodge the deposits, such as placer-type deposits, which is pumped to a processing plant (or gravity separation is performed at the mine site using a sluice). Gold and kaolin are commodies mined using this method. - correct answer Hydraulic mining (surface, aqueous) Also known as strip mining. Used for bedded deposits. Overburden is NOT hauled away but cast directly into the adjacent mined-out cut. Sub methods are area mining (for flat terrain) and countour mining (for mountains). Coal and Phosphate are mined using this method. - correct answer Open cast mining (surface, mechanical)