Mining practices

The western phosphates are sedimentary deposits in adjoining areas of Wyoming, Idaho, and Utah derived from a former inland sea. They consist of layers of limestone, phosphate, and chert, now budded and faulted so they are rarely horizontal. The phosphate ore is strip-mined using large earth-moving equipment such as shovels, scrappers, dump tmcks, and bulldozers to mine the overburden and phosphate ore. Mining ratios of overburden to metric ton of recovered ore are from 1—3 m /1 (2—4 yd /short ton). The typical mining practice is to remove ore and overburden from a pit in discrete layers (Lifts) of 10—20 m in depth. Overburden from the pit is back-hauled to a previously mined pit. Extensive land reclamation practices are later carried out to return the mine areas to natural states. 

Cemented carbides play a cmcial role in the recovery of metallic ores and nonmetals by underground or open-pit mining practices, recovery of minerals such as coal (qv), potash, and trona, and drilling for oh and gas. The methods of excavation can be broadly classified into three types rotary... 

The uranium heap leaching technology is an ex situ adaptation of a 20-year-old heap leach mining (i.e., of gold, silver, and copper) technique used to treat soil. Each soil/contaminant chemical treatment combination is unique and must be developed separately. The equipment required for field-scale uranium heap leaching is basically the same as the equipment used in standard mining practices. 

Modern coal-mining practice tends towards the use of mechanical devices, such as Cardox, Hydrox Mechanical Miners rather than explosives. This will not necessarily reduce the number of coal mine explosions because these may be, and indeed are known to be, initiated by other means such as faulty electrical equipment, breakage of electrical cables or other means of producing a hot spark or arc... 

This kind of situation usually does not occur in coal mining practice, but in fact there have been instances when an explosive charge has been fired across gaps filled with methane inside the shothole. The conditions characteristic of the firing of explosive charges suspended in a methane-air mixture are then very similar to those met in practice. 

King, L. H. et al, Dept, of Mines, Technical Surv., Fuels Mining Practice Div. R114, 1 (1963)... 

Given the local enrichments of arsenic locally present in pyrite of Appalachian Basin coal, enviromnental impacts are possible. Dispersal of arsenic from coal to stream sediments and soils may occur by both natural weathering and mining disturbance. Because arsenic in coal is commonly associated with iron sulfide minerals, much of the arsenic will be avoided by mining practices that favor selection of low sulfur (low pyrite) coal or that remove pyrite from the coal during coal preparation. In addition, disposal of the resulting coal or wash waste could present some concern because arsenic maybe concentrated in these materials. 

Witten IH, Frank E. Data mining Practical machine learning tools and techniques. San Francisco Morgan Kaufmann, 2005. 

The Island Copper Mine in British Columbia, Canada, operated from 1970 through 1995. The reclamation and closure of the mine represent an excellent example of environmentally conscious mining practice. Welchman and Aspinall provided a case history of the mine, which is summarized bcrc. ... 

Abstract Current mining practice allows extracting slightly over one-half of commercial... 

I. H. Witten and E. Frank, Data Mining Practical Machine Learning Tools and Techniques with Java Implementations , Morgan Kaufmann, San Francisco, 2005. 

According to the theory and mining practice of top-coal caving, the short axis Lb of ellipsoid in top-coal caving space can be calculated by the following formula ... 

In order to illustrate the fracturing mechanics during the subsequent excavation, the second excavation after the first excavation shown in Figure 2 is implemented. In mining practices, before an excavation starts, the stress waves produced in the previous excavation have completely vanished. In order to simulate the real mining operations, the second excavation starts after 10 ms of the first detonation, when the stress waves have fully dissipated. At 10 ms, the fragmented rock mass produced by the first excavation is removed and a new-formed tunnel is filled with air, then the subsequent excavation is started to execute. The calculation results of material statuses as a func-... 

Dougherty, J.W., Douglas, J.M. (1940). Mining practice at the Holhnger gold mine. Mining Technology 4(2) 20-21. 

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