In underground mining a hoist or winder is used to raise and lower conveyances within the mine shaft.Modern hoists are normally powered using electric motors, historically with direct current drives utilizing Ward Leonard control machines and later solid-state converters (), however modern large hoists use alternating current drives that are variable frequency controlled.
Rock masses are commonly used as the underlying layer of important structures such as bridges, dams and transportation constructions. The success of a foundation design for such structures mainly depends on the accuracy of estimating the bearing capacity of rock beneath them.
17. Surveying, Mapping and Mine Plans. 1) DEFINITIONS In this Chapter, unless the context indicates otherwise-"bedded mineral deposit" means any reef, coal seam, lode, mineral bed or fissure, which occurs conformably within it's country rock and is not of a massive nature;
The main advantages of laser weapons include: weapon bolt travels at the speed of light, excellent accuracy, damage inflicted by the bolt can be dialed up or down, lasers have no recoil, and the "ammunition" (i.e., electricity required per bolt) is much more inexpensive than the equivalent conventional bullet.
In the case of in-situ leaching (ISL) - also called in-situ recovery (ISR), or solution mining - the uranium-bearing ore is not removed from its geological deposit, but a leaching liquid is injected through wells into the ore deposit, and the uranium-bearing liquid is pumped to the surface from other wells.
I. Introduction A. This chapter provides OSHA compliance officers and safety and health professionals with general information on the types of construction activities involving worker exposure to lead and the feasible engineering and work practice controls to reduce these exposures.