1993-10-04_REVISION - M1988112 - Laserfiche WebLink

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ST DIVISION OF MINERALS AND GEOLOGY Departmem of Natural Resources I J 13 Sherman 51., Room 715 Denver, CO 80203 Phone: 130318667567 FA%:13031 83 2-81 06 October 4, 1993 Ms. Alana Scott Battle Mountain Resources, Inc. Rny Romer Grvenrtrt Michael8 Lung Diviaun Dlrecln! P.O. Box 310 San Luis, CO 81152-0310 Re: Phase II, Raise I Embankment Lift, San Luis Project, File No. M-88-112 Dear Ms. Scott: The Division has reviewed the information submitted with your September 30, 1993 letter requesting approval to continue construction of the embankment. Based on what you have submitted, the Division can grant such approval, however, information gathered during the Division's inspection on October 1, 1993 indicates that the first 10 feet of the raise was constructed with materials that do not meet the specifications in the 'approved design. It is my understanding from discussions with Division management that the use of non-specification material in both construction of the embankment raise, and the drainage blanket, will be presented to the Mined Land Reclamation Board as a possible violation to Permit No. M-88-112. It is possible that the Board will detrermine that the use of the non-specification material is unacceptable; if BMRI chooses to continue construction of the raise, be advised that the materials being used are not currently approved, and may conceivably have to be amended or removed. If BMRI chooses to continue construction, the piezomet:ers should continue to be monitored on a regular basis during and after construction, and the Division notified if any water i:e detected. The settlement monitoring stations should be surveyed dimly during construction of Raise I, and daily surveys should continue after construction until there is no movement (within instrument limitations) for three consecutive days. The stations. should be monitored weekly thereafter until zero movement has been indicated for four consecutive weeks. The concern that the Division has with the construction of Raise I is with the hydraulic conductivity of the non-specifica1~ion borrow material being used to construct the raise. The designiapproved by the Division calls for the use of material with lees than 10 percent fines. This type of material was incorporated into the design to promote desiccation of beach tailing which will form the foundation of Phase II, Raise II. The material from the borrow pit • OF COLORADO pF' CO~ ti.4 ~~ b o r~ , .~~ ~ re~