MINERAL PROSPECTING

Prospecting is synonymous in some ways with mineral exploration which is an organized, large scale and scientific effort undertaken by mineral resource companies to find commercially viable ore deposits.

Prospecting is quite intensive physical labor, involving a considerable amount of traversing (traditionally on foot or on horseback), panning, sifting and outcrop investigation, looking for tell-tale signs of mineralisation

The traditional methods of prospecting involves carefully and intense combing through the countryside, often through creek beds and along ridgelines and hilltops looking for signs of mineralisation in the outcrop.

Once a small occurrence or show was found, it is then necessary to intensively work the area often via the addition of some complex machinery. In some instances and for most base metal, the rock would have been mined by hand and crushed on site and the ore separated from the gangue by hand.

MAGMA DEPOSITS

Pressures and friction in zones of mountain building and release of pressure as a result of failure of the rock also are probable factors in the melting of rocks. Whatever the source of energies involved in its formation, the magma is very important in the field of ore deposits since a great bulk of these deposits is found as a direct result from magma activity.

The term "direct magma deposits" refers to deposits of mineral, which have formed within the body proper of magma mass. As magma ceases to rise and encroach upon the rocks in which has been invading, it begins to cool. The rate depends upon such factors as total amount of heat present and the amount of overlying, insulating rocks present.

PEGMATITES

They separate into localized concentrations and upon solidification of the magma, become ore deposits. As cooling continues minerals continue to crystallize out of the magma solution, the remaining liquid becomes increasingly rich in low temperature minerals, such as quartz, and volatile minerals, such as water.

The great bulk of metallic ore minerals are concentrated in this late-stage residual solution. Pegmatites are vein-like or dike-like formations that often contain very large crystals, some of which are valuable minerals. Usually pegmatites are closely associated with an igneous mass. They likely are the end stage of differentiation of cooling magma.

A large group of important mineral deposits is formed by action of surface agents upon earlier magmatic or hydrothermal deposits. Reworking of older material and reposition or reconcentration by mechanical, chemical or organic means form them.

• MECHANICAL DEPOSITS

  form by concentrating valuable materials with relatively high specific gravities and comparative resistance to chemical and physical breakdown. These are placer deposits. Gold, platinum, tin, monazite, and gemstones occur in mechanical deposits. Other less resistant minerals, such as scheelite, cinnabar and magnetite form when conditions are favorable.

• RESIDUAL DEPOSITS

  form in place by selective leaching and removal of worthless material while the valuable mineral is left behind, thus building a concentration that is worth mining. Examples are iron, manganese, nickel and aluminum deposits.

• CHEMICAL DEPOSITS

  form by the precipitation of material from solution into bodies of surface water such as lakes or seas. Generally, these deposits are non-metallic. An example of these types of deposits are dolomite, gypsum and salt deposits.