REV03144

• Permit No: M1988112
• IBM Index Class Name: Revision
• Doc Date: 11/7/1995
• Doc Name: BMRIS RESPONSE TO TR 15 REQUIREMENTS FOR EVALUATION OF METHODOLOGIES TO DEMONSTRATE THE QUALITY
• From: DMG
• To: JAMES STEVENS BRUCE HUMPHRIES
• Type & Sequence: TR15
• Media Type: D
• Archive: No

• iii iiiiiniiiiiiiii
STATE OF COLORADO
DIVISION OF MINERALS AND GEOLOGY
Deputmern of N, Iural Resources
1 J 13 Sherman Ct., Room ? 15 I`yF ~~~
Denver, Colorado fl0203 Iltll
Phone. [phone]
FA\: 1303) 832~A 106
llEPARTMENT OF
NATURAL
RESOURCES
TO: James Stevens Rov Romer

Bruce Humphries Governor
lames S. Lochhead
Execmive Direclor
FROM: James Dillie f~ • Michael B Long
V! Division Direclor
DATE: November 7, 1995
RE: BMRI'S RESPONSE TO TR-015 - REQUIItEMENTS FOR EVALUATION OF
METHODOLOGIES TO DEMONSTRATE THE QUALTTY OF GROUNDWATER
BENEATH THE TAILINGS FACILITY AND COLLECTION POND
I reviewed BMRI's letter dated October 31, 1995 regarding the above-referenced item.
The fu•st thing I want to do is outline the facts, as supported by test data, which have been agreed
to by BMRI and the Division. Then I will comment on BMRI's response letter item by item.
As noted by previous analyses and borehole data, the Santa Fe aquifer underlies the tailings facility
and collection pond at the depth of 14Q± feet. The material above the aquifer is unsaturated
(vadose zone). The seepage velocity m the Santa Fe aquifer was determined to be 15 feet per year.
The alluvium and the Santa Fe deposits down to and including the aquifer interval is comprised of
heterogeneous material of interbedded clays, silty clays, silts, coarse sand and grdvels. This
mixture of material usually is very impermeable (as indicated by the low seepage velocity). The
recharge area of the Santa Fe aquifer is very small.
In paragraph 1 of BMRI's opening statement {page 1), it is stated that BMRI "is required to outline
the manner in which it will demonstrate to the Division's satisfaction the quality of groundwater
beneath the tailings facility and collection pond." The key words are that BMRI will "demonstrate
to the Division's satisfaction".
BMRI speaks of the angled borehole proposal that was initially submitted but is pow being
discounted, due to potential technical problems and a lack of interest from the various drilling
contractors that were sent bid requests. BMRI contends there are too many risk factors to employ
angled boreholes as a means of evaluating groundwater quality in the Santa Fe aquifer beneath the
tailings facility and the collection pond. BMRI states at the end of paragraph 1 of page 3 "we do