Gravity Concentrators & Jigs Compared
A Gravity Concentrator has the bed fluidized 100% of the time. A Jig is fluidized only 50% of the time. A Gravity Concentrator works at 150 g forces. A Jig works at 1 g. Material is caused to move in a lateral movement through the Gravity Concentrator. A Jig has a lateral movement and a […]
Dry Washer
Dry washers have been used for many years in the Southwestern United States, where water is scarce, and especially in New Mexico where several million dollars in gold has been produced during the last century by dry washing. The Cerrillos, Golden, and Hillsboro districts are among those having produced gold by dry washing. In years […]
Gold Dredging Costs
In the section that immediately follows, specific cost data for dredge operations considered representative in the industry have been updated and listed. Following this is a section on general cost data that correlates operating costs to annual production according to bucket size. These costs cover dredge operations in the Western States. Cost of dredging in […]
Gold Dredge Sizing & Capacity
Determining Suitable Dredge Size: After the placer deposit is properly prospected the miner has a reasonable knowledge of the volume and grade of the placer together with information on its geometry, formation, and the distribution of values by size and location as well as information on bedrock topography, surface topography, water supply, and a host of […]
How to Determine the Value of a Placer Gold Deposit
The functioning and capacity of a dredging system must be keyed to the environmental and natural conditions of climate, water availability, location, and the physical and geologic characteristics of the deposit. The investigation of a placer deposit should be made by or be in charge of an experienced person or organization familiar with how these […]
Heavy Minerals Recovery from Sand & Gravel
We investigated methods for the recovery of byproduct heavy minerals from sand and gravel operations in Oregon and Washington. These heavy minerals are not currently recovered except for gold in a few areas. The recovery of byproduct heavy minerals would provide a domestic source of minerals presently imported, and a more efficient use of domestic […]
Heavy Media Media Recovery – Magnetite & Ferrosilicon
Media Magnetite (Fe3O4) and Ferrosilicon (FeSi) are the most widely used media. Magnetite is used up to a specific gravity of 2.2; a mixture of FeSi and Fe3O4 is used for the range 2.2 to 2.9; above 2.9 FeSi is used alone. Using FeSi, separations up to specific gravity of 3.4 have been made commercially. […]
Elutriation Bowl: Falcon & Knelson
Elutriation Another enhanced gravity device was patented in 1935 by A. N. MacNicol (Figure 4). It is also a truncated cone but ribs divide the length into a series of slots. A water jacket and connecting holes are used to inject water and elutriate a bed of material in each. Some companies have produced this […]
Gold Placer Mining
When a site where gold is known to occur has been found, and after it has been sampled and judged worthy of further effort, the ownership status should be checked to assure that the ground is open for claiming. Then, after staking adequate claims (or arranging to lease if the ground is not open to […]
Gold Dredging Process Plant
Once aboard the dredge, the dredged material is classified, its valuable portion recovered, and its waste portion disposed in a coordinated recovery disposal system designed to handle the capacity of the digging system. Also on board are the dredging-support equipment of the spuds, winches, and controls, and the water-supply systems. The recovery equipment consists of […]