Sinking Large Diameter Mine Shafts by Rotary Drilling
A 6-ft diam core drilling machine has successfully completed seven mine shafts in Virginia and West Virginia to depths as great as 465 ft. There is no practical depth limitation to this new system—a potential method in formations not easily penetrated with other large-scale drilling programs—and higher penetration rates and larger diameters are possible in […]
Semi-Automatic Hoist
A Semi-Automatic hoist has been installed at the 2966 station of the Copper Queen mine, since neither the bulk of supplies handled nor the number of men engaged in developing the 3100 level justifies the constant attendance of two cagers and two hoist operators. The connecting service shaft between the 2966 and 3100 levels is […]
Shaped Explosive Charges
Since the end of World War II interest has been increasing in the use of shaped charges in the mining industry and in other industries using explosives for blasting purposes. Shaped charges employ the principle known as the “Munroe effect,” which was discovered by Charles E. Munroe more than 50 years ago (in 1888). Details […]
Blasting with Ammonium Nitrate
In giving this subject the “broad-brush” treatment, it will be necessary to generalize on the major points which at the same time will permit me to avoid, to a great extent, any involvement in the purely technical and theoretical aspects of blasting. The practice of theorizing before a new idea is tried has practically been […]
Estimating Data for Open Pit Haulage Trucks
In 1955, before planning an accelerated stripping program, Chino Mines Div. began an engineering study to improve data for estimating truck haulage costs for any future haulage layout. The study aimed to develop: 1) significant unit costs, 2) a method of estimating travel time from which truck needs and future stripping rate could be determined, […]
How to Determine the Strength of a Mine Roof
In an earlier phase of the investigation, an experimental room was progressively mined to an areal dimension of 50 by 100 feet. As the dimensions of the room were increased, the roof separated into horizontal layers that were loaded only by their own weight. The maximum stress and the elastic behavior of the lowest roof […]
Small Mine Operation Shattuck Denn’s Bardon Mine
Small tonnage ore bodies can be developed at a profit on a short life basis. Such is the case of the Bardon Mine in the Big Indian Mining District in San Juan County Utah. Faced with a small initial tonnage of high grade uranium ore, the Shattuck Denn Mining Corporation Engineers developed some new ideas […]
Percussion Drilling
The past 15 years have seen rapid advances in the metallurgy of materials for drill machinery and bits, but rock drilling itself continues to be largely an art. Jet piercing, roller bit rotary drilling, and rotary percussion are all promising new techniques, but the percussion rock drill, still used for 90 pct of the blastholes […]
Type of Continuous Miner
While coal production over the past 25 or 30 years has been on a horizontal plane, coal’s share of the total energy market has declined. To participate more effectively in this total energy market, it is necessary to produce coal more efficiently. It is the obligation of all management, employees, and mining departments to gear […]
Reduce Blasting Noise
The public relations problems of users of explosives have greatly increased within the past few years. One reason is that explosives and blasting agents are being consumed in increasing quantities. The principal reason, however, is that more people have become physically affected by blasting. Mines, quarries, and construction sites that were formerly in relatively remote […]