Show modern mining methods mark trona production the most modern modem mining me ghods mark the production of trona at westvaco wyoming site of green rivers great new chemical industry every possible operation if Is automatic including automatic operation of the high speed hoist that brings the trona to the surface for refining at the mine mouth mining of trona if is practically aUy identical with the modern modem methods of coal mining so that the coal miners vt of sweetwater county move in trona mine without having to learn new methods 0 of mining machinery operation interesting to many people is me method of holding the n mine roof in place instead of the use of mine props familiar to so many people the more modern method of bolting the root roof is used long bolts are placed in the rock forma formations U ons overhead overt at regular intervals and then locked into place so that the series of bolts actually hold the overhead burden in one solid piece and prevents it from falling |