Chapter 21: Problem 4

Name the important sources of gold and discuss the extraction methods used for recovery of gold from these sources.

Short Answer

Expert verified

Two important sources of gold are lode deposits and placer deposits. Lode deposits are extracted using a method known as hard rock mining, which involves the use of drills and cyanide solutions. Placer deposits, on the other hand, are extracted using panning, where gravel from river sediments is swirled in a pan with water to separate the gold, or by methods such as dredging or hydraulic mining.

Step by step solution

Identifying the main sources of Gold

Primary gold deposits are formed from gold-bearing fluids at sites where the chemistry and transport to the surface are suitable. These mainly occur in two forms, lode (primary) deposits or placer (secondary) deposits. Gold is often found in alluvial deposits which are sediment deposited by water, and it is also often found in veins of quartz and other rocks.

Discussing extraction methods for Primary deposits

The extraction process used in mining depends on the type of deposit. In the case of lode deposits, the most common method is known as hard rock mining. In this process, gold is first drilled or blasted from the rock and then transported for crushing. After crushing, a method known as froth floatation is used in which oil makes gold particles to float to the top of the water solution and are skimmed off. Then, it is dissolved in a cyanide solution to separate gold from the rest of the crushed rock. The gold-cyanide mixture is heated, during which gold is separated from the cyanide solution.

Discussing extraction methods for Placer deposits

For placer deposits, a common extraction method is gold panning. In this method, gravel from the riverbed is put in a wide, shallow pan, mixed with water, and set to swirl. As the pan swirls, lighter material is carried away by the water, and heavier gold-bearing sediments are left at the bottom of the pan. Likewise, placer deposits can also be extracted by dredging or hydraulic mining, which involves high-pressure water jets used to disintegrate sediment layers.

Unlock Step-by-Step Solutions & Ace Your Exams!

Full Textbook Solutions
Get detailed explanations and key concepts
Unlimited Al creation
Al flashcards, explanations, exams and more...
Ads-free access
To over 500 millions flashcards
Money-back guarantee
We refund you if you fail your exam.

Start your free trial

Over 30 million students worldwide already upgrade their learning with Vaia!

Recommended explanations on Chemistry Textbooks

View all explanations

What do you think about this solution?

We value your feedback to improve our textbook solutions.

Name the important sources of gold and discuss the extraction methods used for recovery of gold from these sources.

Short Answer

Step by step solution

Identifying the main sources of Gold

Discussing extraction methods for Primary deposits

Discussing extraction methods for Placer deposits

One App. One Place for Learning.

Most popular questions from this chapter

Recommended explanations on Chemistry Textbooks

Chemical Analysis

Nuclear Chemistry

The Earths Atmosphere

Chemistry Branches

Ionic and Molecular Compounds

Physical Chemistry

Study anywhere. Anytime. Across all devices.