Abrasion, Absorption, Accretion Acicular, Adamantine

• Abrasion: Wearing away or erosion by friction.
• Abrasive: Substance used to grind or polish other materials.
• Absorb: The sucking up or retention of liquid by a solid.
• Absorption: The act of being absorbed, as water in a sponge.
• Accretion: The accumulation of material by physical or chemical means.
• Acicular: Slender and straight, such as needle-shaped crystals.
• Acid: A salt or dissolved compound of hydrogen wherein one or more atoms of hydrogen may be displaced by a metal ion.
• Acidic: Characterized by a predominance of acid-forming minerals.
• Acre-foot: Amount of water that will cover 1 acre to a depth of 1 foot.
• Acre: A unit of land measure equal to 43,560 square feet.
• Activated Charcoal: Carbon, mostly of vegetable origin, and of high absorptive capacity.
• Adamantine: Having a diamond-like luster or hardness.
• Adhere: To stick to an unlike substance.
• Adhesion: The sticking together of two or more unlike substances.
• Adit: A tunnel driven horizontally into the side of a mountain or hill to gain access to mineral deposits for exploration or mining. Also horizontal, or near horizontal passage, driven from the surface for the working of the mine.
• Adjusted value: An analytical result that has been increased or decreased by an amount necessary to compensate for known, or suspected, variables in sampling analyses. Also called "corrected value".
• Adobe: A general term for several types of sticky clays; also used to describe dried bricks of clay and straw, and buildings made of same.
• Adsorb: The physical or chemical sticking of dissolved substances to the surface of solid materials.
• Adsorption: The process of being adsorbed, as in the absorption of precious metals on activated carbon.
• Aerial: Airborne or suspended in air.
• Afterdamp: Unbreathable gases remaining after an underground explosion.
• Agate: A waxy variety of chalcedony or quartz, a semiprecious stone.
• Agglomerate: To gather or form into a rounded mass; also type of breccia.
• Agglomeration: A concentration process based on the adhesion of pulp particles to water. Loosely bonded associations of particles and bubbles are formed that are heavier than water; flowing-film gravity concentration is used to separate the agglomerates from non agglomerated particles before placing on a leaching pad. Forming crushed ores into pellets by mixing with concrete
• Aggregate: Common term for gravels; also to gather or bring together.
• Ainlay bowl: A wet gravity concentrator used to revolve heavy placer minerals by centrifugal force.
• Airplane drill: A light and compact engine powered placer drill designed for use in areas that are difficult to access.
• Alignment: Lining-up or adjusting to a standard.
• Alkali: Whitish, crusted salts on soils created by evaporation; also basic salt containing calcium, sodium or potassium, etc.
• Alliaceous: Mineral having a garlic-like odor; arsenical compounds.
• Allotropy: The ability of some minerals to exist in two or more forms.
• Alloy: A solid mixture or combination of two or more metals.
• Alluvial: Pertaining to soil and gravel deposited by water action; related to gravels, silt and mud formed and deposited by water movement. Alluvial (or bench) deposits contain untapped potential for finding gold because such areas have never been worked before.
• Alumina: A mineral composed primarily of aluminum oxides.
• Amalgam: An alloy or union of mercury with another metal: gold or other metal that has been coated with mercury by adhesion.
• Amalgamation: Removing precious metals from ores by use of mercury.
• Amorphous: Without definite form; no crystalline structure.
• Analysis: The determination of the contents in any substance.
• Anhydrous: Refers to compounds having no water in their composition.
• Anneal: Heating and cooling metals to make them harder and stronger. Annual labor: Yearly assessment work on unpatented mining claims.
• Anode: Generally refers to impure copper cast into a special shape for incorporating into an electrolytic refinery for the final purification process.
• Anomaly: A geological feature, esp. in the subsurface, distinguished by geological, geophysical, or geochemical means, which is different from the general surroundings and is often of potential economic value, and usually suggests the possibility of a mineral deposit.
• Anticline: An elevated fold in rock strata, such as a ridge.
• Apex: The highest point of anything, such as a vein, outcrop or hill.
• Aqua Regia: Acid mixture of 3 parts hydrochloric and 1 part nitric acid.
• Aqueous: Containing water or related to material deposited by water.
• Aquifer: A rock formation or basin containing water. Also An underground geological zone which is able to store or conduct water in reasonably large quantities.
• Arbitrage: To simultaneously buy and sell a commodity or security in different markets to take advantage of price differentials.
• Arborescent: Minerals that branch in treelike forms.
• Archean: Refers to rock group of the Archean geological era.
• Argentiferous: Pertains to silver-bearing rocks.
• Argillaceous: Consisting of clay or having a clayey nature.
• Argillic: Pertaining to clay or clay minerals; e.g. "argillic alteration" in which certain minerals of a rock are converted to minerals of the clay group.
• Arrastra: Crude stone mill for grinding and amalgamating gold ores.
• Arsenical: Pertaining to or containing arsenic.
• Arsenopyrite: A tin-white or silver-white to steel-gray mineral. Arsenopyrite occurs chiefly in crystalline rocks and esp. in lead and silver veins, and is constitutes the principal ore of arsenic.
• Ash-Flow Tuff: A tuff deposited by an ash flow or gaseous cloud; a type of roc k formed by the widespread deposition and consolidation of ash flows and swiftly flowing, turbulent gaseous clouds erupting from a volcano.
• Assay Value: The value of an ore as determined by assay results; the amount and worth of metals or minerals in a sample.
• Assay-ton: Assaying equivalent ton, equal to 29.166 grams.
• Assay: The determination of the type and quantity of metals or minerals in an ore; an analytical determination of the metal or mineral content in a sample. To chemically test the purity of metal. Also refers to the lab procedure and final result.
• Assessment Work: Annual work on unpatented claims required by mining law.
• Atomic Weight: The relative weight of an atom of an element as compared to the most stable isotope of carbon (At. Wt.12.01115).
• At-the-Money: An option whose strike price is equal, or approximately equal, to the current market price of the underlying futures contract.
• Attrition: Loss of material through friction and abrasion.
• Auriferous: Refers to gold-bearing rocks and gravels.
• Autoclave system: Oxidation process in which high temperatures and pressures are applied to convert refractory sulphide mineralization into amenable oxide ore.
• Autochthonous: Formed or produced in the place where now found. The term is widely applied.
• Autogenous grinding: A secondary grinding system where material is tumbled in a revolving cylinder with no steel rods or balls taking part in the operation.
• Avoirdupois: Common system of weights used in the U.S. and Britain.
• Axis: The centerline of a crystal, object or rotating shaft.