gangue
The useless rock mixed in with the valuable mineral. It has to be separated and discarded during processing.
Technisch gesehen: Gangue comprises the minerals in an ore that have no commercial value in the context of the operation and must be separated from the target mineral during beneficiation. Its composition matters practically because certain gangue minerals — clays, talc, pyrrhotite — complicate flotation, leaching or smelting. The term is specific to the unwanted mineral fraction; the broader term for all displaced non-ore material is waste rock.
Geology
geophysics
Geophysics is the science of using physical measurements — such as gravity, magnetism, or electrical signals — to work out what kinds of rock or minerals lie underground without having to dig there first.
Technisch gesehen: Applied geophysics in mineral exploration encompasses a range of techniques — including magnetics, gravity, seismic reflection, induced polarisation, electromagnetic, and radiometric surveys — that detect contrasts in physical rock properties such as density, magnetic susceptibility, electrical resistivity, and radioactive emission. Results are interpreted as anomalies relative to background, which then guide drill targeting rather than directly confirming the presence of ore. Geophysics is distinct from geochemistry, which measures elemental concentrations; the two disciplines are complementary and are routinely integrated in exploration programmes.
Geology
grade
How much of the valuable substance is in the rock, usually expressed as a small fraction — for example, grams of gold per tonne of rock, or a percentage of copper.
Technisch gesehen: Grade is the concentration of a target commodity within a sample, block, or orebody, expressed in units appropriate to the commodity — mass percent for base metals, grams per tonne for gold and platinum-group elements, parts per million for trace elements, and carats per hundred tonnes for diamonds. Average grade must always be qualified by the volume or mass it represents, because a high-grade but small intersection and a low-grade but large one can carry identical contained metal. Grade as reported in a resource statement is a block-averaged figure, not a point measurement.
Geology
grain boundary diffusion
Atoms moving through a solid by travelling along the narrow gaps between the tiny crystal grains that make up a metal, which is much faster than moving through the grains themselves.
Technisch gesehen: Grain boundary diffusion is the transport of atoms along the two-dimensional disordered zone between adjacent crystalline grains in a polycrystalline solid. Diffusion coefficients along grain boundaries are orders of magnitude higher than lattice diffusion coefficients within the bulk grain at the same temperature, so grain boundaries dominate mass transport at lower temperatures. In rare-earth magnet manufacturing, grain boundary diffusion treatment is used to introduce heavy rare-earth elements — typically dysprosium or terbium — into the surface regions of sintered neodymium-iron-boron magnets, improving coercivity while minimising the total quantity of heavy rare earth required.
Materials
greenfield
A greenfield project is an exploration effort in a place where no mining has ever taken place before, so the company is starting completely from scratch with no existing information about what lies underground.
Technisch gesehen: A greenfield exploration project is one conducted in an area with no prior mining or significant modern exploration history, meaning there is no inherited infrastructure, no historical drill database, and no existing resource to guide targeting. Risk at the greenfield stage is highest because the geological model is largely unvalidated, but so is the potential for a discovery that has no historical discount applied to its scale. The term is routinely contrasted with brownfield, and in practice the boundary between the two is not always sharp: an area near a historical mine but geologically untested may be treated as greenfield for modelling purposes.
Geology
gross weight
The total weight of a shipment including the packaging, container or vehicle, not just the goods inside.
Technisch gesehen: Gross weight is the combined mass of a consignment and all its packaging, dunnage or container, as opposed to net weight, which refers to the commodity alone, or dry metric tonne, which additionally excludes moisture. In bulk mineral trade the distinction between gross, net and dry-basis weights matters because payment is typically made on dry contained-metal tonnes, meaning that moisture content and packaging must be deducted before the commercially relevant quantity is established.
Materials