Alluvial mining

Aquatic or marine mining is the removal of unconsoUdated minerals that are near or under water, with processes in which the extracted mineral is moved by or processed in the associated water. This type of mining may also be referred to as alluvial mining or placer mining. The two major types of aquatic or marine mining are dredging and hydraulicking. 

Iridium occurs uncombined in nature with platinum and other metals of this family in alluvial deposits. It is recovered as a by-product from the nickel mining industry. 

To meet the extraordinary conditions existing in this deposit, said he, I decided that the only way to mine this sulphur was to melt it in the ground and pump it to the surface in the form of a liquid.. .. At that time, the drilling of a well in an alluvial deposit containing quicksand, etc., was a very tedious task, and it took from six to nine months to get through the alluvial material to the rock-work which we do today in three days.. . . When everything was ready to make the first trial,... 

Tin-mining methods depend on the character of the deposit. Primary deposits are embedded in undeiground granitic rock and recovery methods are complex. The more important secondary deposits are in the form of an alluvial mud in the stream beds and placers and the recovery is simpler than lode mining. Cassiterite is recovered from alluvial deposits by dredging, hydraulicking where a head of water permits it, jets and gravel pumps on level... 

Diamonds were first discovered in India as early as about 800 BC. The early diamond mines were the alluvial gravel in the banks or beds of active or dried up rivers in which diamond and other heavy and hard crystals had been concentrated by the action of the flooding water. The most famous Indian mine was at Kollur near Hyderabad where several historical diamonds (the chief among them being the Koh-i-Nur) were found. Although most of the Indian diamond mines dried up by the 18 century, the mines at Panna in Madhya Pradesh are still operational and some new fields in the vicinity are soon to be opened for commercial exploitation. 

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