Backfill, Backfilling, Backwash Ball Mill , Base Metal

• Backfill: Replacing material removed from an excavation. The process of refilling an excavation, a mine opening, or the space around a foundation.
• Backfilling: Waste material used to fill the void created by mining an ore body.
• Backwardation: A market situation in which prices are progressively lower in future months than in the nearest month. A backwardation market generally reflects a near-term shortage of commodity, hence the premium price for current delivery.
• Backwash: Water movement against the primary direction of flow.
• Badlands: A barren or extremely rough terrain.
• Baffle: A partition or grating in a furnace, container or channel.
• Bailer: Device for removing sludge and water from a drill hole or mine.
• Ball mill: A steel cylinder loaded with steel balls into which crushed ore is fed. The ball mill is rotated, causing the balls to cascade and grind the ore. A rotating horizontal cylinder with a diameter almost equal to the length supported by a frame or shaft, in which nonmetallic materials are ground using various types of grinding media such as quartz pebbles, porcelain balls, etc.
• Banded: Pertains to layered rocks or rock formations.
• Bar: A metal rod with chiseled end used for prying; also refers to an accumulation of gravel in watercourse.
• Basalt: General term for all dark-colored volcanic rocks.
• Base metal: Any common useful metal, excepting the precious metals. (a) Any of the more common and more chemically active metals, e.g. lead, copper. (b) The principal metal of an alloy, e.g. the copper in brass.
• Base: Any compound that will combine with an acid and neutralize it, forming a salt: also bottom or support for any structure.
• Basic: Underlying fundamental; rocks with little silica; also the opposite of acidic.
• Basis: The difference between the spot or cash price of a commodity. Basis is calculated to the nearby position and may represent different time periods, product forms, grades and locations, depending on the cash and futures prices used.
• Batholith: A large mass of igneous rock extending to a great depth.
• Bear Market: A market in which prices are declining.
• Bed: Perhaps the most common term in geology, meaning layer or stratum. Quarrymen usually mean by beds not the stone beds in the geologist's sense but the partings between them.
• Bedded: Refers to rock formations deposited in successive layers.
• Bedrock: Solid rock beneath topsoils and gravel deposits.
• Bench: Natural or man-made step-like terraces. 1. In an underground mine, a long horizontal face or ledge of ore in a stope or working place. 2. The horizontal step or floor along which coal, ore, stone, or overburden is worked or quarried.
• Bid: A proposal to buy a specific quantity of a metal or a futures contract at a given price; opposite of offer.
• Bid/Ask: Bid (or buy) is the price a dealer will pay for gold bullion or coins. Ask (or sell) is the selling price offered by a dealer.
• Bit: The hardened cutting end that attaches to drill rod.
• Black gold: Placer gold that is coated with black manganese oxides.
• Blade: A flattened, elongate mineral crystal.
• Blast hole: A hole drilled for emplacement of explosives. A hole drilled in a material to be blasted, for the purpose of containing an explosive charge.
• Blasting: Detonating explosives to loosen rock for excavation.
• Boiling Point: The point at which a substance boils; for water, 212 degrees F. or 100 degrees C.
• Borehole: Common term for a drill hole.
• Borer: Common term for rock-cutting drill.
• Bort: An impure diamond used for hardening drill bits; an abrasive.
• Bortryoidal: Refers to mineral occurring in globular forms.
• Brace: Mine timber; also platform over mouth of vertical shaft.
• Breaker: Slang term for a rock crusher.
• Breast: The working face of a placer drift, normally underground.
• Breccia: An altered rock composed of angular fragments cemented together in a matrix material. A coarse-grained clastic rock, composed of angular broken rock fragments held together by a mineral cement or in a fine-grained matrix. The fragments have sharp edges and unworn corners.
• Brittle: Easily fractured or broken.
• Bucket line dredge: A large dredge that utilizes a chain of buckets to excavate and lift gravels for processing.
• Bulkhead: Partition erected to seal off certain portions of mines.
• Bulldozing: Moving material with mechanized equipment.
• Bullion: Precious metals in the form of bars, wafers, or ingots of .995 purity or finer. Also called "dore" or "zoo".
• Bull Market: A market in which prices are rising.
• Butte: An isolated hill or mountain with steep sides.
• Button: Refers to precious metal globule produced by fire assaying.
• By-product: A secondary product, usually another mineral recovered in the mining and processing of the primary mineral. A secondary metal or mineral product recovered in the milling process.