Hard rock mining

Hard rock mining of these ore bodies requkes drilling and blasting with ammonium nitrate and dynamite. After blasting, the ore is reduced in size with a drop ball and then loaded on tmcks for transportation to the processing plant. Mica, quartz, and feldspar concentrates are separated, recovered, and sold from the hard rock ore. 

Mining of the ore deposit constitutes a significant cost, especially in hard rock mining. Mining costs vary considerably from ore to ore and from a few cents to well over 100/t mined. Underground mining is the most expensive hydrauHc mining of sedimentary deposits is the least expensive. 

Lundin, F. E., J. W. Lloyd, E. M. Smith, V. E. Archer and D. A. Holaday, Mortality of uranium miners in relation to radiation exposure, hard-rock mining and cigarette smoking-1950 through September 1967, Hlth. Phys., 16 571-578 (1969). 

There are two types of caverns used for storing liquids. Hard rock (mined) caverns are constructed by mining rock formations such as shale, granite, limestone, and many other types of rock. Solution-mined caverns are constructed by dissolution processes, i.e., solution mining or leaching a mineral deposit, most often salt (sodium chloride). The salt deposit may take the form of a massive salt dome or thinner layers of bedded salt that are stratified between layers of rock. Hard rock and solution-mined caverns have been constructed in the United States and many other parts of the world. 

Other releases could include use of gear oil packages, fluids used in hard rock mining and equipment use in other types of mining, fluids and equipment used in oil and gas exploration, manufacture of seamless pipe, metalworking and operation of turbines on ships [20]. 

Pyrite Sulfides Tidal marshes (reducing conditions and hard-rock mine tailings (coal and shale beds) C Primary mineral (oxidizing conditions) but secondary phase forms in reducing environments large metal and acidity input to surface waters during weathering... 

Figure 5.60 shows the fracture surface of a bolt from a hard rock mine. 

Milne D, Hadjigeorgiou J Pakalnis R. 1998. Rock mass characterization for tmderground hard rock mines. Tunnelling and Underground Space Technology (13) 383 391. 

Saharan, M. R., Mitri, H. S. (2009). Numerical Simulationfor Rock Fracturing by Destress Blasting-As Applied to Hard Rock Mining Conditions. Berlin VDM Verlag. ISBN 978-3-639-11064-7... 

Coal Mining 434 Ore Mining and Dressing (Hard Rock Mining) 440... 

Mine management may want to identify the type of emergency most likely to occur and plan accordingly, focusing on such an emergency. But a word of caution is needed about that concept. Before the Sunshine Mine Fire Disaster, no one believed such a disaster could occur in a hard-rock mine. Unfortunately, that supposition was wrong. The entire mining industry learned many lessons from that disaster. 

Underground Mining (paraphrased from Grayson 1999) Hard-rock mining generally employs the... 

Often times following analysis, remedial measures of various types are needed to control actively changing conditions. For example in underground coal mines, installation of cribs (of various stiffness and types), trusses, rib or floor bolts, cable bolts, and different types of roof bolts may be used to supplement the initial method of support. In hard-rock mines, supports may be added where none were used initially. 

The exposure of workers to respirable dust in hard-rock mines, including both metal and nonmetal mines, may be reduced by a systematic approach that includes all or some of the practices discussed in this section. 

White, B.G., J.K. Whyatt, and D.F. Scott. 1995. Geologic factors in rock bursts in the Coeur d Alene mining district. In Proceedings Mechanics and Mitigation of Violent Failure in Coal and Hard Rock Mines. USBM SP 01-95. 217-230. 

Most of the required science for most mining hazards is now well understood (with one or two notable exceptions, for example, rock bursts in deep hard rock mines). However, even when the science is known and the necessary control measures are fiiUy understood and documented for all to follow, the real control and the everyday rehability of risk management, hes in the hands of the people at the mine. If methane monitoring standards are not maintained, if effective dust control measures are not introduced, if PPE is not worn, if mles and procedures are not used, etc. then all the hard won knowledge which, theoretically, allows us to control risk will have been wasted. 

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