Mining Engineers

Before the decision is made to mine a newly discovered mineral deposit, mining engineers must go through successive stages of information gathering, evaluation, and planning. As long as they judge the project to be economically viable, they proceed to the next stage. Review and planning for a major mining project may take a decade or longer and may cost many millions of dollars.

First mining engineers try to get a general idea of the deposit's potential. They accomplish this by reviewing geological data, product marketing information, and government requirements for permits, public hearings, and environmental protection. Based on this review, they prepare rough cost estimates and economic analyses. If it appears possible to mine the deposit at a competitive price with an acceptable return on investment, mining engineers undertake a more detailed review.

Meanwhile, geologists continue to explore the mineral deposit in order to ascertain its dimensions and character. Once the deposit has been reasonably well defined, mining engineers estimate the percentage of the deposit that can be profitably extracted. This estimate, which takes into account the ore's grade (value) and tonnage (volume and density), constitutes the minable ore reserve. It provides mining engineers with enough specific information to refine their economic appraisal and justify further analysis.

At this stage, engineers begin the process of selecting the most suitable mining method—one that will yield the largest profit consistent with safety and efficient ore extraction. In considering the adaptability of mining methods to the deposit, they rely heavily on rock mechanics and geologic data. Measurements of the stresses, strains, and displacements in the rock surrounding the ore body help engineers predict roof-support requirements and settling of rock masses during excavation. Evaluation of the deposit's geologic features (such as the dimensions, inclination, strength, and physical character of the ore and overlying rock) enables engineers to place mine openings in stable rock, avoid underground water, and plan overall excavation procedures. If the evaluation calls for surface mining, engineers must decide where to dig the pits and where to put the rock and soil removed during mining.

Having estimated the ore reserve, chosen a mining method, and begun mine planning, engineers can determine daily (or yearly) mine output tonnage in light of product demand. They also select equipment and help plan and size the mine's plant, support, ore processing, and shipping facilities.

For underground mining, mining engineers must determine the number and location of mine shafts, tunnels, and main extraction openings. They must also determine the size, number, kind, and layout of the various pieces of equipment. If the project continues to appear economically viable, construction begins.

As actual mine-making proceeds, mining engineers supervise operations. They train crews of workers and supervisors. The stress fields around the mine workings change as the mine expands. Engineers and engineering technicians must inspect the roof of underground cavities to ensure that it continues to have adequate support. Engineers must also continually monitor the quality of air in the mine to ensure proper ventilation. In addition, mining engineers inspect and repair mining equipment. Some mining engineers help plan ways of restoring or reclaiming the land around mine sites so that it can be used for other purposes.

Some mining engineers specialize in designing equipment used to excavate and operate mines. This equipment typically includes ventilation systems, earth- and rock-moving conveyors, and underground railroads and elevators. Engineers also design the equipment that chips and cuts rock and coal. Others select and determine the placement of explosives used to blast ore deposits.

Mining engineers also work for firms that sell mining supplies and equipment. Experienced mining engineers teach in colleges and universities and serve as independent consultants to industry and government.