D7301 - Underground Hardrock Mining

Operational Details
Underground hardrock mining is generally a process of tunnelling into the earth to locate and extract the mineral deposit. Majority of the work is mechanized and computerized.

This classification includes underground hardrock mining starting with the exploration phase through to the refinement of the mineral. Firms in this category would include those whose main work includes exploring or prospecting for deposits; shaft sinking and maintenance; mining and extraction, processing the material and distribution of the material.

Exploration or prospect work includes: geological mapping, rock and soil sampling, geological, geophysical and geochemical surveys and line slashing or line cutting. Depending on the stage of exploration, these activities may take place underground as well as above ground. Soil sampling may include core (small amounts) as well as bulk sampling (large quantities that are mined out). The majority of exploration firms are included in this rate code.

Examples of types of equipment used for exploration include: seismic, electromagnetic, gravimetric, radiometric, radar and remote sensing equipment, etc. Line cutting may involve: power or chain saws, and brush mowers. Equipment underground may include all-terrain vehicles, trucks, automatic miners, power and hydraulic mining tools, rotor continuous boring machines, blowers, conveyors, etc.

Underground uranium mining generally involves the following process: A vertical opening (shaft is sunk) is excavated from the surface to the ore body elevation. Horizontal openings in the rock are excavated parallel to the ore body to complete underground exploration. When mining is proven feasible, a raisebore drill is moved into the raisebore chamber. The raise bore turns a 3 meter reamer, which mechanically grinds through the ore body. As the reamer progresses, the ore falls to the bottom of the raise where it is collected by a scoop. The scoop tram delivers the reamed ore to the sag mill grizzly where it enters the grinding circuit. The grinding process takes the ore down to a size that is manageable for the extraction of uranium from raw ore. Transporting the ore slurry from the underground operation to surface storage tanks. The slurry is transferred from storage tanks to the ore mix tank, which is used to control the shipping grade. Trucks in turn take the slurry for further processing. The primary use of uranium is fuel for nuclear reactors.

Generally other underground hardrock mining will follow similar process of shaft sinking, tunnelling, removal of mineral and refinement. Refinement or processing of the mineral will be dependent upon the type of mineral extracted, and may be on or off site.

Examples of occupations in hardrock underground mining include: geologists, geophysicists, line cutters or slashers, blasters, mine operators, mine engineers, equipment operators, heavy duty mechanics, shaft technicians, maintenance workers, raise bore operators, process operators, scoop operators, construction workers, mine helper, sandblasting personnel, carpenters, machinists, power engineers, industrial electricians, industrial mechanics, welders and millwrights. The mill or processing plant employees include: metallurgists, instrumentation mechanics, laboratory technicians, mine engineers, mechanical engineers, processing personnel, mill operators, warehouse workers, etc.

SIC Codes
000000378 - Geophysical/geological work
000000380 - Prospecting, mineral exploration
000000381 - Geophysical survey
000000384 - Underground Hardrock mining
000000387 - Blasting
000000388 - Underground mine maintenance
000000389 - Grouting/cement work in mine
000000390 - Crosscutting, shaft sinking