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<br />• • III Illlllllllllllll <br />99,3 <br />.--~c~tv~.C~ <br />MAR 3 0 2000 <br />Division of Minerals 8 Gcoloyy <br />March 27.2000 <br />Gregg Squire <br />Division of Minerals and Geology <br />1313 Sherman St., Room 215 <br />Denver, CO 80203 <br />AGGREGATE <br />INDUSTRIES <br />RE: Blasting Complaint at the Morrison OuarrV, Permit #M1973-021 <br />Dear Gregg: <br />The following information pertains [o the complaint letter dated February 23, 2000. In <br />the letter, Mr. Robert Smith listed dates where our blasting activities have produced <br />"tremors" and caused his home to "shake". <br />I have attached a spreadsheet with the blasting dates noted by Mr. Smith and our <br />corresponding blasting information. All blasts were monitored within 1500 feet. From <br />Augur[ 12, 1999 through October 1, 1999, you will notice a "X" in the inch second and <br />dbi columns. Our equipment was reading the blast, but failed to produce a tape, <br />documenting the blast. A rental seismograph, and outside monitoring company (Vibra- <br />Tech) was used while repairs were made to the unit. <br />Mr. Smith called me last summer regarding a blasting complaint, and as his letter states, <br />we monitored a comparable blast at his house, k did not register on the seismograph. <br />Because I did not hear from Mr. Smith, I assumed, that our blasting activities were; not a <br />concern. How disheartening to discover that Mr. Smith monitored 22 blasts that he <br />considered problematic! <br />We have purchased an additional seismograph. so we can use one l.mit to monitor near the <br />blast, and the other unit we can monitor outside our properly boundaries. I'm not sure if <br />these measures will provide relief to Mr: Smith. As you know, the U.S. Bureau of Mines <br />(USBM) established a standard of .50 inches per second as a tlveshold to prevent <br />minimal damage to residential structures., However, this standard does not mean that a <br />blast will not be heard or slightly felt, it means that the Ulast will nol cause damage to <br />strnctures inclose proximity. <br />AGGREGATE INDUSTRIES MANAGEMENT INC <br />3605 South Teller Street <br />Lakewood, Colorado 80235 <br />United States of America <br />Telephone: (303) 985-1070 <br />Faaimile' (303) 716-5315 <br />M K,GIIEG41E IX WSIWES 0.C Cnmp,ry <br />