Glossary of Mining Terms

Glossary of Mining Feasibility Studies

Mining feasibility studies are an evaluation of a proposed mining project to determine whether the mineral resource can be mined economically.

There are three types of feasibility study used in mining:

1. Scoping Studies - Scoping studies are an initial financial appraisal of an indicated mineral resource. Depending on the size of the project a scoping study may be carried out by a single individual. It will involve a preliminary mine plan, and is the basis for determining whether or not to proceed forward with an exploration program, and more detailed engineering work. Scoping studies are developed copying plans and factoring known costs from existing projects completed elsewhere.

2. Pre-feasibility Studies (PFS) - Pre-feasibility studies are more detailed than order of magnitude studies. A preliminary feasibility study is used in due diligence work, determining whether or not to proceed with a detailed feasibility and as a gauge to determine areas within the project that require more attention. Pre-feasibility studies are done by factoring known unit costs and estimating gross dimensions or quantities once conceptual engineering and mine design has been completed. Pre-feasibility studies can be completed by specialist consultants.

3. Detailed Definitive Feasibility Studies (DFS) - Detailed feasibility studies are the most detailed and will determine definitively whether or not to proceed with the project. A detailed feasibility study will be the basis for capital appropriation, and will provide the budget figures for the project. Detailed feasibility studies require a significant amount of formal engineering work.

Glossary of Terms*
Aeromagnetic survey A geophysical survey using a magnetometer aboard, or towed behind, an aircraft.
Airborne survey A survey made from an aircraft to obtain photographs, or measure magnetic properties, radioactivity, etc.
Alloy A compound of two or more metals.
Alluvium Relatively recent deposits of sedimentary material laid down in river beds, flood plains, lakes, or at the base of mountain slopes. (adj. alluvial).
Amorphous A term applied to rocks or minerals that possess no definite crystal structure or form, such as amorphous carbon and obsidian.
Anomaly  Any departure from the norm which may indicate the presence of mineralisation in the underlying bedrock.
Anticline An arch or fold in layers of rock shaped like the crest of a wave.
Assay A chemical test performed on a sample of ores or minerals to determine the amount of valuable metals contained.
Basement rocks The underlying or older rock mass. Often refers to rocks of Precambrian age which may be covered by younger rocks.
Base metal Any non-precious metal (e.g. copper, lead, zinc and nickel etc).
Cut-off grade A grade below which samples are not included in a resources or reserve.
Decline A sloping underground opening for machine access from level to level or from  surface; also called a ramp.
Deposit A body of rock containing valuable minerals; usage generally restricted to zones of mineralisation whose size has been wholly or partly determined through sampling.
Diamond drill A rotary type of rock drill that cuts a core of rock that is recovered in long cylindrical sections, two cm or more in diameter.
Dip The angle at which a vein, structure or rock bed is inclined from the horizontal as measured at right angles to the strike.
Environmental impact study A written report, compiled prior to a production decision, that examines the effects proposed mining activities will have on the natural surroundings.
Fold Any bending or wrinkling of the rock strata.
Fracture A break in the rock, the opening of which allows mineral-bearing solutions to enter.  A “cross-fracture” is a minor break extending at more-or-less right angles to the direction of the principal fractures.
Geophysical survey A scientific method of prospecting that measures the physical properties of rock formations. Common properties investigated include magnetism, specific gravity, electrical conductivity and radioactivity.
Grade The concentration of metal or valuable mineral in a body of rock, usually expressed as a percentage or in grams per tonne or ounces per ton; also, the concentration of metal in a mill concentrate or matte. 
Greenstone belt An area underlain by metamorphosed volcanic and sedimentary rocks, usually in a continental shield. 
Head grade The average grade of ore fed into a mill.
Hematite An oxide of iron, and one of that metal’s most common ore minerals.
High grade Rich ore. As a verb, it refers to selective mining of the best ore in a deposit.
Intrusion A body of igneous rock formed by the consolidation of magma intruded into other rocks, in contrast to lavas, which are extruded upon the surface.
Laterite A residual soil, usually found in tropical countries, out of which silica has been leached. May form orebodies of iron, nickel, cobalt, bauxite and manganese.
Mafic Igneous rocks composed mostly of dark, iron- and magnesium-rich minerals.
Massive sulphide A body of rock made up mainly or wholly of sulphide minerals, such as pyrite, pyrrhotite, or chalcopyrite; often proves to be an orebody. Also, a mineral deposit occurring in massive-sulphide form.
Measured resource A resource whose size and grade have been estimated from sampling at places spaced closely enough that its continuity is essentially confirmed.
Metamorphic rocks Rocks which have undergone a change in texture or composition as the result of heat/or pressure.
Mineral Resource A concentration or occurrence of material of intrinsic economic interest in or on the Earth’s crust in such form, quality and quantity that there are reasonable prospects for eventual economic extraction. The location, quantity, grade, geological characteristics and continuity of a Mineral Resource are known, estimated or interpreted from specific geological evidence and knowledge. Mineral Resources are sub-divided, in order of increasing geological confidence, into Inferred, Indicated and Measured categories.
Ore Reserve The economically mineable part of a Measured and/or Indicated Mineral Resource. It includes diluting materials and allowances for losses, which may occur when the material is mined. Appropriate assessments and studies have been carried out, and include consideration of and modification by realistically assumed mining, metallurgical, economic, marketing, legal, environmental, social and governmental factors. These assessments demonstrate at the time of reporting that extraction could reasonably be justified. Ore Reserves are sub-divided in order of increasing confidence into Probable Ore Reserves and Proved Ore Reserves.
Quartz Common rock-forming mineral consisting of silicon and oxygen.
Quartzite A metamorphic rock formed by the transformation of sandstone by heat and pressure.
Reverse circulation (RC) A drilling method in which a rotating bit cuts rock or compacted earth into fragments, which are flushed upward to the drill collar by air or water or fluid mixtures for sampling. Unlike diamond drilling, it does not provide an intact core for examination or sampling.
Rock Chip sample A method of sampling a rock exposure whereby a regular series of small chips of rock are broken off along a line across the face.
Sedimentary rocks Secondary rocks formed from material derived from other rocks and laid down under water. Examples include limestone, shale and sandstone.
Shear or shearing The deformation of rocks by lateral movement along innumerable parallel planes, generally resulting from pressure and producing such metamorphic structures as cleavage and schistosity.
Step-out drilling Holes drilled to intersect a hoped-for continuation of a mineralised horizon or structure along strike or down dip.
Sulphide ore An ore composed mainly of sulphide minerals; in gold deposits in tropical or arid regions, the primary ore in unweathered rock below the zone of weathering.
Trend The direction, in the horizontal place, of a linear geological feature, such as an ore zone, measured from true north.
Vein A fissure, fault or crack in a rock filled by minerals that have travelled upwards from some deep source.
Weathering The destruction or alteration of primary minerals in a rock; also erosion.
Zone of oxidation The upper portion of an orebody that has been oxidized.

*All terms are sourced from ‘Mining Explained - A Layman’s Guide’ published by The Northern Miner’ and from the ‘Joint Ore Reserve Committee’ (JORC) code of practice.