Longwall Pillar Design Method
The past decade has provided a wealth of practical experience with longwall pillar design. Design formulas developed specifically for longwalls have proven their value in numerous applications. Analytic methods, including numerical models, have also made important contributions. These advances have been based on basic research into abutment loads, coal pillar mechanics, and the interaction between […]
Estimate Recoverable Ore Reserves
The limitations that ore reserve estimators have faced in the past while trying to estimate recoverable reserves stem from different aspects. There are several factors that curtail the effectiveness of the “traditional” geostatistical models: A variogram model is required to derive the VCF; it is well-known that the VCF value itself is greatly influenced by […]
Evaluate Underground Pillar Stress
Strain relief measurement techniques were used to quantify stress in the underground pillar and to compare stress relief to seismic and ultrasonic core velocities. These measurements represent a single point. The procedure for measuring strain relief (Girard and others, 1997) consists of — Drilling a hole 152 mm (6 in) in diameter to a pre-selected […]
Explosive to Maximize Rock Permeability
Explosive Selection to Maximize Permeability Enhancement: As can be seen from the previous sections the single most important scaling parameter is the postshot cavity radius or sprung hole diameter. From Figures 5 and 7 it can be seen that permeability enhancement is considerably diminished at a distance of 6-10 rc from the center of the hole. […]
Control Water Flow during Shaft Sinking
The importance of controlling water inflow during shaft development has been well known to those faced with the problem. Depending on the amount, temperature, and quality of the water, the extra costs of working in wet conditions can easily be several times that for the same work under dry conditions. I have heard estimates of […]
How to Size a Water Spray Systems
Determine what diameter piping is necessary to obtain sufficient water flow to spray nozzles used for dust suppression. A simplified, diagrammatic method of calculating the flow of water through a proposed system consisting of a supply line and two banks of spray nozzles is outlined. How it Works The pressure versus flowrate of the supply at […]
Mining Methods VS Underground Crusher Location
In Section 2 we dismissed those “big-room” applications not needing fundamentally new equipment, and lumped all the rest together. Now, as we examine specific mine types, it is appropriate to differentiate within these categories the manner in which portable crushers might be used, and the consequent effect on desired machine parameters. The common yardstick by […]
Mine Haulage
The haulage system employed to convey coal from the face to the outside, dates back to 300 B. C., when slaves carried the mineral from the face to the consumer. The British discovered coal on their island about 800 A. D. and they were the first people to make practical use of coal and make […]
Longwall Mining
I was requested to write an article on Longwall Mining a short time ago; however, the time has been so short that I have not had time to prepare an article as I would like to have presented it to this body. In writing this article it has not been my intention in making comparison […]
Diamond Drill Sampling Methods
In diamond-drill work, a true sample consists of all the material cut by the bit—both core and cuttings. As the recovery of this sample is the object of diamond drilling, the utmost care should be taken to secure it. Speed of drilling and low costs are of little value if an inaccurate sample is obtained. […]