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tSTGTE OF COLOR40O NI~t~~Nl~ O. L, ~•V"^~••~ DEPARTMENT OF NATURAL RESOURCES D. Monte Pascoe, Executive Dhectnr ~1INED LAND RF.~:LAMA'I'ION 423 Centennial Building, 7373 Sherman street Denver, Colorado 80203 Tel. (303) 866-3567 iiiiiiiiiiiniiiiii 999 David C. Shelton Director DATE: October 19, 1982 TO: Dan Mathews ., FROM: Jim Pendl e ton `'"~ ~µ_ t ~~ RE: Subsidence Mon; Coring an, Bear No. 3 Pfi ne Z have reviewed the document entitled "Subsidence Monitoring Plan, No. 3 Mine", which you forwarded to me. The document, prepared by Bear Coal Company, was submitted in compliance with Stipulation No of the Bear mine permanent program permit, No. C-033-8I. Bear IS As the findings documentfor the Bear No. 3 mine permit explains, the Division imposed Stipulation No. IS upon permit approval because it was concerned that the stability of ancient and modern landslide deposits could be affected by differential surface subsidence, if it were to occur, above the Bear No. 3 underground workings, (See page 87 of the attached findings document) Bear Coal Company proposes the installation of three additional subsidence monuments above the first area which will be retreat mined within the No. 3 mine. These rronuments should provide valid information concerning the magnitude of subsidence, if it occurs, within those areas. In addition, however, the Division considers it prudent to install several subsidence monuments within the landslide deposits of specific concern above the underground workings. The attached xerox excerpt from Bear Coal Company's amended rap E-3, indicates two additional monument locations which the Division believes it would be appropriate to monitor. (See monument No. 10 and No. 11 on attached xeroxed excerpt of map E-3) With~~the addition of these monuments, as well as any bench narks or additional monuments required to complete survey of the additional monuments, the Division would consider the subsidence ionitoring plan to be.acceptable.