Gold Rush Mining Lexicon Gold Rush Alaska

posted: 04/11/12
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If you're a rookie gold miner like most of the Gold Rush crew, there are lots of specialized terms and equipment that make up the core knowledge set for understanding the processes and challenges of gold mining. Here are the basics that have been covered in the show — the essentials that all gold buffs need to know:


This mining method involves searching for gold in ancient layers of sediment, known as alluvial deposits. These layers are composed of tiny bits of gravel, sand and minerals eroded from hard rock by moving water long ago. Alluvial deposits are found in virtually every area where gold is found in hard rock, or lode, deposits. They may be in rivers and streams, but they also can be found thousands of feet from the nearest body of water. In the United States, placer mining began in the Appalachian region in the late 1700s, but it was the discovery of a placer deposit along the American River in 1848 that triggered the California Gold Rush and the explosive growth of placer mining. Up to the present day, roughly two-thirds of the gold discovered in California has come from placer deposits.

Placer mining is very different from mining gold deposits embedded in hard rock, which requires miners to use explosives and crush rocks to extract gold. Instead of brute force, placer miners rely upon gravity, water flow, vibration and magnetism to separate gold nuggets and fine dust from the alluvial material. While placer mining conjures up up images of grizzled prospectors panning in streams, modern larger-scale placer mining operations use complex equipment to separate gold from the detritus. Some placer mining operations even use dredges to churn though huge quantities of alluvial material.


Alluvial material consists of larger pieces of gravel and smaller, finer particles. The finer material usually contains the gold, which is why it's called "pay dirt." Gold miners first separate the pay dirt from the gravel, and then sift more carefully through the pay dirt to extract the gold.

Watch Video: Pay Streaks and Glory Holes - Picking a place to start digging for gold means finding out where old river beds have left behind now buried pay streaks.


This is a more general excavation and mining term, rather than one exclusive to gold mining. A glory hole is a big, impressive-looking excavation that's open to the surface. It can be either the top end of a deep mine shaft, or an open-pit mine. Sometimes a mining process called block caving, in which ore is removed from a tunnel, causes the underground excavation to collapse, forming a glory hole. In typical alluvial gold mining, it can also refers to the eroded out depression formed at the base of an ancient waterfall. Because this concave geometry is known to be ideal for gold concentration, these glory holes are much sought after deposits.

If you're a rookie gold miner like most of the Gold Rush crew, there are lots of specialized terms and equipment that make up the core knowledge set for understanding the processes and challenges of gold mining. Here are the basics that have been covered in the show - the essentials that all gold buffs need to know:


Since the first prospectors waded into California streams with pans in the mid-19th century, the process for separating gold from other material in an alluvial deposit has involved gravity, vibration and water flow. A wash plant is a series of machines — the equivalent of a factory assembly line — that systematically subjects the alluvial material to those forces, and does it more efficiently and handles far larger quantities than a human being could do by hand. The exact configuration of the wash plant varies from one gold placer mining operation to another. Generally, alluvial material is dumped down a chute, and then washed down a slope with water, which helps to separate the gravel from the finer particles that are more likely to include gold. Vibration from a shaker causes those bigger pieces of rock to drop out, while the smaller particles drop through to a sluice box and are sifted through woven rubber matting, which may catch some of the gold. The remaining material may go to a processing tent, where devices like a wave machine and a magnetic separator are used to separate black sand and other material, extracting whatever fine gold particles are mixed in. While 19th century prospectors usually were only able to recover about 60 percent of the gold from alluvial material, modern equipment can recover as much as 90 percent.

Watch Video: Veteran Wash Plant— Neighbor and gold mining veteran John Schnabel shows Todd and his crew how a proper gold wash plant can make you rich.


A shaker is a device that uses vibration to separate out pieces of gravel from the alluvial material. Usually, it's a table, and more than half of the table's surface is covered with small riffles no more than an inch high. A motor, typically mounted to the side, drives a small arm that shakes the table along its length. Shakers are effective for recovering particles of gold down to 5 microns in size. Shakers vary in size, from small 3-and-a-half-foot miniature versions to 15-foot-long tables that can process up to 175 tons of material in a day.


This device, which has been in use since the early days of California gold mining, is a grate of parallel bars that permits the finer particles of material to pass down the sluice, while catching and discarding larger stones. As California historian Charles Beebe Turrill once explained: "If a grizzly is used, a drop of a few feet is necessary, as the material which passes through the grating must drop into a series of sluice-boxes underneath, and thus is carried further from the mining ground." A modern, high-tech gold mining machine called the Derocker, marketed by RMS-Ross Corporation, includes an automatic, spring-loaded feeder and a set of self-cleaning Grizzly bars.

Watch Video: Dakota Fred's Grizzly Bars — Veteran miner Fred Hurt decides to remove a couple of grizzly bars to speed up the wash plant flow, but he fails to check with Harness first.

If you're a rookie gold miner like most of the Gold Rush crew, there are lots of specialized terms and equipment that make up the core knowledge set for understanding the challenges of gold mining or even working your own claim. Here are the basics that have been covered in the show — the essentials that all gold miners need to know:


This is a sheet of metal attached to the bottom of the shaker. The plate has holes; smaller particles of alluvial material, including gold, slip through the holes, but bigger pieces of gravel do not. Mining equipment companies offer punch plates designed to catch various sizes of alluvial pieces, but some miners also make their own custom punch plates.


In the wash plant, this is a sloping channel through which the alluvial material is funneled, so that gravel and sand can be separated from gold. A trough can be equipped with combinations of various devices, such as sluice boxes, riffles and miner's moss, each of which help to separate, trap and extract the precious metal.

Watch Video: Packed With Gold — After running dirt with Fred's wash plant changes, the miners do a cleanout of the sluices and find their first real nugget.


This equipment is used to extract gold from the smaller rock particles and other material in pay dirt. Basically, a sluice is a long, narrow box, or a series of boxes. The pay dirt is dumped into the sluice, and washed with a stream of water. The small particles of gravel are washed away, but the gold, which is heavier and denser, stays behind. The first sluice boxes were developed in the 19th century, and improved versions of the same technology is still in use today. In fact, numerous Web sites offer amateur gold miners instructions on how to build their own sluice boxes from inexpensive materials.


Riffles are small barriers built into a sluice box. As the material flows down the channel, it accumulates at the riffles, and sand beds are formed. In the process, riffles also create turbulence in the water, which causes heavier particles to separate and tumble downward. An overhanging lip on the barrier, known as a Hungarian riffle, is used to increase the turbulence behind the barrier, which agitates the accumulated sand bed itself, causing fine gold to separate and making it easier to recover. Periodically, the material accumulated in the riffles is washed out, so that larger pieces of gold can be removed and the remainder sifted for finer particles.

If you're a rookie gold miner like most of the Gold Rush crew, there are lots of specialized terms and equipment that make up the core knowledge set for understanding the processes and challenges of gold mining. Here are the basics that have been covered in the show — the essentials that all gold buffs need to know:


Over the years, placer miners have used a variety of materials, ranging from pieces of carpet to courdoroy and denim fabric, to catch gold flakes from the material that comes out of the sluice. Today, however, they usually rely on specially-made mats woven from tough strands of rubber or some similar material. (Think of the entrance mats homeowners put out to catch the mud and dirt from visitors' shoes.) When alluvial material that comes out of the sluice is dumped onto miner's moss, the heavier gold particles tend to stick in the nooks and crannies of the matting. That material is then washed out of the mats and processed.

Watch Video: Missing Miners Mossurl] — Just as the crew starts running dirt again they discover that Dorsey forgot to put the critical miner's moss back in the sluice.


A trommel is a cylinder with wrap-around screened panels; it's used to separate alluvial material by size. Basically, the material is fed into the trommel, which is then rotated and washed with water, so that the material is lifted up and aerated. That action is repeated, until the finer material — or the material most likely to include gold — is separated from larger pieces. The fine material slips through the mesh in the screens and is sent to the jigs. The larger pieces stay inside the trommel and tumble toward the downward end, where they're discarded.


Jigging is one of the oldest methods of using gravity to separate and concentrate gold particles. A jig is an open tank filled with water. At the tip of the tank is a horizontal metal or rubber screen with a coarse, heavy filter, known as ragging. A spigot is at the bottom of the tank to remove the concentrate. After alluvial material goes into the jig, mechanical plungers cause the water to pulse up and down. This lifts away the lighter particles of sand, while the heavier particles, including gold, collect at the bottom of the tank. That material is collected and sent to the processing tent.


This device is used to separate gold particles from wet alluvial material, which is called slurry. The table has a tray, which is attached to weights and springs. The latter are precision-engineered so that when they bump the tray, they create small waves that undulate through the material. The lighter sand rises, while the heavier particles, including gold flake, slip to the bottom and in the opposite direction of the flow of the slurry. The bump frequency and velocity, along with the angle of the table, can be adjusted, depending on the size of the particles miners want to recover.

Watch Video: Wave Table Basicsurl]


A magnetic separator extracts iron particles from alluvial material, increasing the fineness of the mixture. In some configurations, the alluvial material passes along a conveyor belt equipped with electric-powered magnets beneath it. The iron is attracted by the magnets, while the gold and other non-magnetic material continues to move down the line

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