INSPEC15197 - Laserfiche WebLink

Home Browse Search

(Page 31 MINE ID # OR PROSPECTING ID # M-1986-076 INSPECTION DATE 7/16/03 INSPECTOR'S INITIALS RCO The revision to be submitted for the tailings pond must include adequate engineering anaysis of the existing slope: surface gradient, topsoil, talus, weathered rock and bedrock. Stability is of key importance: excavating a bench to hold tailings will create steeper slopes, which might become unstable under load of fine tailings. If tailings areas are to be "stair-stepped" up the hill, placement of additional levels on top of earlier levels might create unstable conditions. Is the floor of the pond to be built into bedrock? Will embankments be keyed into stable slope material? The revision must include these items, plus maps and cross sections. The areas below this bench were not inspected. These include the roads down to the open draining adit. Weed control and drainage work is to be performed by the operator along the road sections. The adit is not backfilled but is kept boarded up to prevent unauthorized entry. Groundwater sampling is carried out from the underground sump. The operator stated that water quality samples were taken (from underground and from the gulch), and the analyses will be submitted to this office soon. The operator is reminded that another sample is to be obtained later this year from each site. For additional discussion of this please see the 8/14/02 and 10/31 /02 letters from this inspector to the operator.) The new tailings pond, like the former one, will be unlined, which necessitates that careful neutralization be ensured. The method of tailings neutralization carried out was discussed. Sodium hypochlorite is added to the tailings slurry, to the amount that a certain pH is reached. The water of the slurry drains off from the mill sump, and the tails are trammed down to the pond for disposal. The operator must provide specific information as to the pH maintained in the mill, the pH attained for neutralizing the tails, the method and frequency of pH sampling, and the length of time the tails spend draining in the sump. No further items were observed or discussed during the inspection. At this time there are no problems. The bond is considered adequate, but a detailed recalculation will be performed after review of any upcoming changes, with new figures to be forwarded to the operator. Responses to this inspection report should be directed to the Division of Minerals and Geology, 701 Camino del Rio, Room 125, Durango, Colorado 81301, Attn: Bob Oswald; phone no. 970-247-5193. I & E Contact Address NAME OPERATOR STREET CITY/STATE/ZIP James Bender Deadwood Gulch Mining Co. 5529 US Hwv 64 Farmington, NM 87401 cc: Harry Posey, DMG ^ CE ^ BL ^ FS ^ HW ^ HMWMD ICH) ^ SE ^ WOCD ICHI ^ OTHER cc: William T. Burris, President, Incas Mines, Inc., 21677 Mounts Field Dr., Golden, CO 80401 CERTIFICATE OF SERVICE I, Bob Oswald, certify that I mailed a copy of this entire document to the addressee and all others specified herein to receive copies (DMG personnel excepted) on the signature date shown on page one, by depositing it in the first class mail of the US Postal Service. Signed ~~h (/~i'w`i"'~-