What are the placer deposites? Give example of minrals found in such deposites
Answers
Answer:
Placer deposits being characteristically stratified with layers of mineral concentration, particularly in bedrock, sampling becomes a troublesome job. In the event that the placer concentrations are coarse in size, the impact of nugget effect can be significant on the determination of the average (mean) concentration. Thus placer sampling requires adequate collection of materials from bedrock as larger-sized bulk samples. Because the value of a placer deposit depends on the recoverability of the minerals by gravity methods, the sample volume is measured and a part of the sample is ordinarily concentrated in a sluice box and panned for a preliminary estimate of the minerals and values.
Answer:
Minerals that form placer deposits have high specific gravity, are chemically resistant to weathering, and are durable; such minerals include gold, platinum, cassiterite, magnetite, chromite, ilmenite, rutile, native copper, zircon, monazite, and various gemstones.