show me various types of gold mining dredges

Because gold is far denser than most rock (19.3 g/cc as opposed to about 2.7 g/cc) it settles into little pockets between large rocks or into bedrock fissures. Ongoing weathering and erosion of rock outcrops continuously exposes new fragments of gold that wash downstream.

The sources of all placer gold are “lodes”, or veins of gold naturally formed within the rock. Placer mining targets “native” gold that isn’t chemically bound up within the rock itself. Some modern commercial placer operations are quite large and utilize heavy equipment and river diversions. All of these techniques use gravity and water to separate the dense gold from the lighter sand and gravel. Placer mining takes a variety of forms, including panning, “sluice-boxing”, hydraulic mining, and dredging. The stereotypical grizzled gold-rush prospector panning for gold was searching for “placer gold”, or gold deposited in a waterway. MODERN PLACER MINING - An massive abandoned dredge can be seen in the background of this modern placer mining operation. Hardrock mines can be either underground mines or strip mines, and are usually more environmentally destructive than placer mining. Most ore accessed this way today contains only microscopic grains of gold, and it takes tons of rock to produce ounces of gold. Today, gold is extracted in hardrock mines that directly mine the source rock, or “lode” of gold, where it was originally deposited by geochemical processes. Some early miners also used an early form of hardrock mining, digging solid veins of gold out of rock, where mineralized water had deposited it over thousands of years. Historically, the majority of gold was mined from “placer deposits”, where gold has settled out of an existing or ancient waterway downstream of where nuggets had eroded out of rock outcrops.

There are strange things done in the midnight sun

Show me various types of gold mining dredges