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• • III IIIIIIIIIIIIIIII <br />STATE OF COLORADO <br />Roy Romer, Gove <br />DEPARTMENT OF NATURAL RESOURCES <br />MINED LAND RECLAMATION DIVISION <br />DAVID C. SHELTON, Director <br />MEMORANDUM <br />ne 1987 <br />T0: Greg Squire ~ / ll X <br />FROM: Jim Pendleton 4,,,,,~y-'~-- <br />RE: Trapper Mine - qua Response to Blasting Concerns - PR No. 1 <br />(Permit No: C-81-010) <br />I have reviewed the response submitted by Trapper Mining Company, addressing <br />my earlier concern regarding the potential impacts of their proposed surface <br />blasting upon the workings of the Eagle No. 5 mine. The company has provided <br />a discussion of Eagle No. 5 mine pillar stability determinations which attests <br />that the pillars are considerably oversized. They have also communicated with <br />the U. S. Bureau of Mines blasting experts and determined that peak particle <br />velocities of under 4.0 in/second will not detrimentally affect pillar <br />strength in the workings. <br />My only remaining concern is one of possible increase in pillar spalling annd <br />roof fall in the affected workings. Trapper observes that much of the <br />workings within the affected area are abandoned. The areas which are active <br />will be protected by providing warning to Empire and blasting during shift <br />change when no one would be within the affected workings. <br />This combination of responses suffices to satisfy my concerns regarding <br />potential hazardous exposure within the underground workings. <br />cc: Mike Long <br />423 Centennial Building, 1313 Sherman Street Denver, Colorado 80203-2273 Tel. (303) 866-3567 <br />