|
List Of Articles : A |
Acid deposition
see acid rain.
|
Acid mine drainage (AMD)
see also acid mine water. Discharge of acid solutions from mine workings is usually known as Acid Mine Drainage (AMD).
|
Acid mine water
Mine water (drainage) that contains free sulfuric acid, mainly due to the weathering of iron pyrites. Many of the most difficult and expensive environmental problems faced by mining companies result from acid mine water. Sulfide minerals such as pyrite and pyrrhotite are commonly associated with many ore types, and it is the oxidation of these minerals and subsequent leaching of their acidic oxidation products including sulfuric acid that leads to acid mine water. As if generation of acid itself is not of sufficient concern, the potential for widespread and possibly far-reaching environmental damage is aggravated in many situations, by the presence of ‘heavy metals’ such as manganese, copper, arsenic and zinc which may dissolve in acidic solutions, thereby becoming mobilized and, potentially, ‘bio-available’.
|
Acid mine water
Mine water (drainage) that contains free sulfuric acid, mainly due to the weathering of iron pyrites. Many of the most difficult and expensive environmental problems faced by mining companies result from acid mine water. Sulfide minerals such as pyrite and pyrrhotite are commonly associated with many ore types, and it is the oxidation of these minerals and subsequent leaching of their acidic oxidation products including sulfuric acid that leads to acid mine water. As if generation of acid itself is not of sufficient concern, the potential for widespread and possibly far-reaching environmental damage is aggravated in many situations, by the presence of ‘heavy metals’ such as manganese, copper, arsenic and zinc which may dissolve in acidic solutions, thereby becoming mobilized and, potentially, ‘bio-available’.
|
Acid neutralization capacity (ANC)
Acid-base accounting involves measurement of the maximum potential acidity (MPA) and the acid neutralizing capacity (ANC), with net acid producing potential (NAPP) calculated as the difference between the two values. The MPA is calculated from the total sulfur content, determined by the Leco furnace method. The ANC represents the inherent acid buffering of the sample. It is determined by the Modified Sobek method in which the sample is reacted with hydrochloric acid (HCl), followed by back-titrating with sodium hydroxide (NaCl) to quantify the unreacted HCl. The acid consumed by the reaction (HCl added minus unreacted HCl) is then expressed as kg H2SO4/t of sample
|
Acid producing potential (APP)
see acid neutralization capacity
|
Acid rain
Refers loosely to a mixture of wet and dry deposition (e.g. rain) from the atmosphere containing above normal amount of nitric and sulfuric acids. The precursors or chemical forerunners of acid rain formation result from both natural sources, such as volcanoes and decaying vegetation, and man-made sources, primarily emissions of sulfur and nitrogen oxides resulting from fossil fuel combustion (oil and coal with high sulfur content).
|
Acid rock drainage (ARD)
see acid mine water.
|
Acid treatment
Acid treatment is the process of soaking activated carbon granules in a dilute hydrochloric acid solution to dissolve calcium carbonate and other impurities that have become absorbed in the carbon and that thereby reduce the ability to adsorb the targeted element (e.g. gold).
|
Active workings
Any place in a mine where miners are normally required to work or travel.
|
Adit
A passage from the ground surface by which a mine is entered and/or dewatered.
|
Aeromagnetic
measurement of the strength and orientation of the earth’s magnetic field acquired using an airborne instrument
|
Ag
the symbol for silver (Argentium) on the Periodic Table
|
Agitation
In metallurgy, the act or state of being stirred or shaken mechanically, sometimes accomplished by the introduction of compressed air.
|
Airway
Any passage through which air is carried; also known as an air course.
|
Amalgamation
Amalgamation consists of alloying mercury to gold and silver. Gold and silver are separated simply by heating the alloy to evaporate the mercury.
|
Angle of dip
The angle at which strata or mineral deposits are inclined to the horizontal plane.
|
Angle of repose
The maximum angle from horizontal at which a given material will rest on a given surface without sliding or rolling.
|
Anode
A rectangular metal plate with positive charge cast in a shape suitable for refining by the electrolytic process.
|
Anomaly
an area which exploration has shown to be different from the surrounding area or region
|
Anticline
An upward fold or arch of rock strata.
|
APELL (Awareness and Preparedness for Emergencies at Local Level)
APELL is a strategic program that provides detailed guidelines for the development and implementation of emergency response plans in local communities.
|
Aquifer
A water-bearing geological formation.
|
Artisanal mining
Artisanal mining is defined as small-scale mineral extraction, using mainly manual methods, carried out by individuals or small family groups.
|
Asbestos
Asbestos is a commercial term used for a group of six naturally occurring fibrous silicate minerals.
|
Assay
A chemical test by wet or fire methods performed on a rock sample to determine the amount of valuable metal contained.
|
Au
the symbol for gold (Aurum) on the Periodic Table.
|
Audit
The nature and type of environmental audits varies with the objective of the audit. A mine audit aims to evaluate the environmental performance of the mine.
|
Auger
A rotary drill that uses a screw device to penetrate, break, and then transport the drilled material.
|
Autogenous grinding
The process of grinding ore with ore in a rotating cylindrical mill using large pieces of ore instead of steel rods or balls.
|
Auxiliary operations
All activities supportive of but not contributing directly to mining.
|