APPCOR10775

• Permit No: C1981041
• IBM Index Class Name: Application Correspondence
• Doc Date: 6/4/1982
• Doc Name: POWDERHORN COAL CO SUPPLEMENTAL SUBMITTAL IN RESPONSE TO SUBSIDENCE CONCERNS FOR THE COTTONW
• From: JIM PENDLETON
• To: JIM HERRON
• Media Type: D
• Archive: No

STATE OF COLORADO RICH ARD D. l• Gov mnm
DEPARTMENT OF NATURAL RESOURCES
D. Monte Pascoe, Executive Director
MINED LAND RECLAMATI(1N
423 Centennial Building, 7373 Sherman Sfreet
Denver, Colorado 80203 Tel. [phone]
June 4, 1982
iiiiiiiiiiiiiiiiii
David C. Shelton
Director
TO: Jim Herron ~ -1r--
FROM: Jim Pendleton ~~+^~-
RE: Powderhorn Coa Comp y's Supplemental Submittal in Response
to Subsidence erns for the Cottonwood Lease Area
Pursuant to your request, I have reviewed the supplemental response submitted
by Powderhorn Coal Company addressing our earlier concerns regarding subsidence
impacts within the Cottonwood lease area. The response, dated May 20, 1982,
has several remaining deficiencies. For continuity, I will address my comments
in relation to the topics discussed in my earlier memo to you, dated February
10, 1982.
Ute Water District P1 ant
Earlier application materials proposed to undermine the Ute Water District's
water treatment plant, several water storage tanks, and a 24-inch diameter
water distribution pipeline. Discussions with Powderhorn Coal Company indicated
that the company had decided not to undermine these water plant facilities.
However, no reference is contained to those facilities within the supplemental
response. The applicant should amend the application to either include a
detailed subsidence control plan for those facilities or to delete that portion
of the mining plan. In either instance, the applicant should amend 19ap RSOl-02-006
(originally labeled Exhibit 5), entitled "Mine Plan - Life of Operation" to
indicate the location of these Water District facilities.
Alluvial Deposits and Potential Alluvial Valley Floors
The original application does not appear to contain sufficient descriptions of
the Cottonwood and Rapid Creek drainages to discount the existence of alluvial
deposits, alluvial aquifers or potential alluvial valley floors within those
drainages. The applicant has submitted some additonal information within the
supplemental submittal materials. That information is, however, insufficient
to discount the existence of potential alluvial valley floors within portions
of Section 1 and 2 at the northwestern corner of the Cottonwood Lease tract.
Assuming, in the worst case, that these areas do constitute alluvial valley
floors, the hydrologic functions of the Cottonwood and Rapid Creeks, which supply
water to this alluvial valley floor, must be kept hydrologically intact. In
addition, if sufficient alluvial deposits and alluvial aquifers exist in
connection with the two creek channels, these renewable resource lands must be
protected from material damage through effects of subsidence. The exact aerial
extent of these alluvial materials must be delineated by appropriate field mapping.