Small Mine Selective Blasting
January 2000 by Dr. Ralph E. PrayDrill holes in a mineralized vein often penetrate hidden layers of poor ore which, after blasting, end up diluting the production quality. Disseminated gold ores carrying two ounces per ton may be identical in appearance to adjacent vein material...
…more difficult terrain must be traversed in the hope of locating small pockets, low depressions or small gullies on needle-covered slopes.
Most dry washers have a feed rate adjustment. It needs to be set so that the material flows evenly over the riffles and does not bury them.
• The ESA used, and apparently abused, in Arizona and New Mexico
• In a somewhat related story...
• Among the numerous bills that died when Congress adjourned...
• More on the ESA
• Miners must present proof of filing, says IBLA
• Federal government backs mining project
• Appeals Court says Clinton roadless rule can stay
This remote goldfield covers an area of over 13,000 square miles of the Savanna Gulf country of Far North Queensland, Australia.
Colorado-Utah-Wyoming oil shale was first reliably discovered to contain gold and silver by the U.S. Bureau of Mines in the 1920s. Although most of this vast shale resource, up to 1,000 feet in thickness, contained nil or barely detectable values, many brown shale samples fire assayed here over the past thirty years have yielded up to 0.02 ounces per ton (opt) Au and 2.0 opt Ag.
Although there are many mining ghost towns in California, it is rare to find the ruins of one that was abandoned 140 years ago and then subsequently buried by hydraulic mining debris.
The Bawl Mill • Over the Divide • Our Readers Say • Letter from the Editor to our Readers and Advertisers • Administration Considers Bypassing Congress • First Woman to Draw Mining Pension • Mohave Mountain Placers, Arizona • High Court to Reconsider Wilderness Water Rights • Sixteen to One Takes on MSHA • Picks & Pans: Gold Mining on Joie Osgood Ranch • Gold • Company Notes • Millie's Tailings • Placer PGMs in Alaska • Mogollon—New Mexico's Remote Gold Camp • ICMJ 9th Annual Photo Contest Results • The Other Minerals of Mt. Diablo • Melman on Gold & Silver • Mining Stock Quotes and Mineral & Metal Prices • Looking Back