| Bio Leaching |
A process for recovering metals from low-grade ores by dissolving them in solution, the dissolution being aided by bacterial action. |
| Bonanza |
The discovery of an exceptionally rich vein of gold or silver. |
| Borasca |
An unproductive mine or claim; the opposite of a bonanza. |
| Claim |
A parcel of land in a gold field that a person was legally entitled to mine because he had staked it out and recorded his title. The dimensions varied according to local custom. |
| Coyoting |
A method used by miners to reach gold deposits resting on bedrock without excavating all of the overlying soil. After a vertical shaft was sunk, tunnels radiating like wheel spokes were dug along the bedrock. |
| Cross-cut |
A mine tunnel going across an ore vein, used for ventilation and communication between work areas. |
| Drift |
A mine tunnel following the direction or drift of a vein; opposite of a cross-cut. |
| Environmental
Impact Study |
A written report, compiled prior to a production decision, that examines the effects proposed mining activities will have on the natural surroundings. |
| Flume |
An inclined channel, usually of wood and often supported by a trestle, for conveying water from a distance to be utilized for various purposes including placer mining. |
| Hard Rock |
Ore that could be removed only by blasting as opposed to ore that could be worked with hand tools. |
| Hydraulic Mining |
A method of mining by washing the ore out of the ground with a powerful jet of water as from a hose. |
| Leaching |
A chemical process for the extraction of valuable minerals from ore: also, a natural process by which ground waters dissolve minerals, thus leaving the rock with a smaller proportion of some of the minerals than it contained originally. |
| Lode |
A clearly defined vein of rich ore. The principal vein in a region was called the "mother lode." |
| Open Pit Mining |
Open pit mining is the most common method mining porphyry copper and these open pits account for some of the largest man made holes in the world. When determining the size of an open pit the normal ratio is 50% of the shortest distance across. In other words if a deposit is 800 ft long by 600 ft wide, the pit can be 300 feet deep. This is because the ramps need to be wide enough to allow large trucks to go up and down. |
| Outcrop |
An exposure of rock or mineral deposit that can be seen on surface, i.e. that is not covered by soil or water. |
| Oxidation |
A chemical reaction caused by exposure to oxygen that results in a change in the chemical composition of a mineral. The reason oxides are attractive to copper and gold explorers is because they are usually easier to process and are usually higher concentrations of ore. |
| Placer |
A deposit of sand, dirt or clay, often in an active or ancient stream bed, containing fine particles of gold or silver, which could be mined by washing. |
| Quartz |
A crystalline mineral, often transparent, in which gold and silver veins were most commonly found. |
| Refine |
To reduce to a fine, unmixed, or pure state; to free from impurities, as to refine gold or silver. |
