A2 Economic Deposits, Extraction and Processing Flashcards
Ore
the rock containing valuable metal(s) that is economic to mine.
Resource
a useful and valuable natural material.
Mineral resources
can be metallic and non- metallic or industrial minerals.
Reserves
the amount of the resource that can be extracted at a profit using existing technology.
Ore deposit
an accumulation of metal that may be economic to mine.
Average crustal abundance
describes the amount of metal in ‘average’ continental crust.
Concentration factor
the amount by which the metal is concentrated to make an ore deposit.
Ore mineral
a mineral containing valuable metal(s).
Gangue mineral
a low-value waste mineral.
Grade
refers to the concentration of valuable mineral within an ore.
Cut-off grade
the grade below which it is uneconomical to mine.
Secondary enrichment
occurs when metals are leached from within surface rocks and precipitated just below the water table.
Chemical weathering
the in situ breakdown of rocks at the Earth’s surface due to chemical reactions.
Leaching
where ions are dissolved from rocks and carried downwards in solution.
Gossan
an insoluble cap of iron oxides at the surface of a mineral vein.
Oxidising
describes oxygen-rich conditions, allowing elements to combine with oxygen to form oxides.
Reducing
describes oxygen-poor, anoxic conditions.
Enriched deposit
a zone of high-grade ore just below the water table, formed by secondary enrichment.
Porphyry
a large igneous intrusion with a porphyritic texture.
Dredging
where material is scraped or sucked from the river or sea bed.
Hydraulic mining
the use of high-pressure water jets to dislodge material.