GENERAL31745

• Permit No: C1983058
• IBM Index Class Name: General Documents
• Doc Date: 11/1/1983
• Doc Name: PROPOSED DECISION AND FINDINGS OF COMPLIANCE
• Permit Index Doc Type: FINDINGS
• Media Type: D
• Archive: No

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3) When the air shaft pump was destroyed in ~197~due to collapse of the
air shaft, another hole was drilled into the western portion of the
mine. The western drill hole had to go deeper to intersect the mine
workings, yet this drill hole was dry. After the dry hole, the town
consulted the old mine maps and drilled a hole into the eastern portion
of the mine into the old mine sump. Water was encountered in this upper
pool. This drill hole is the current location of the pump which could
supply the Coal Creek water right;
4) The water quality from the existing Caldirola Mine we1J is much
better than would be expected from water which had been in contact with
the roof and floor rock of the mine for an extended period of time (See
the water quality table in the cumulative hydrologic impacts section of
this document). It appears that the source of this water is from a
nearby surface recharge zone.
The probable hydrologic impacts of the Twin Pines No. 2 Mine on the water
which supplies the Caldirola Mine well water right is negligible. Mining as
proposed will probably lower the level of water within the lower portion of
the abandoned Caldirola Mine. However, the upper portion which is the source
of water for the Caldirola Mine well water right will not be affected. Twin
Pines Coal Company, Inc., proposes to mine southeast downdip to the axis of
the Chandler Syncline, then proceed along the axis to the southern permit
boundary. The abandoned Caldirola Mine lies updip, or higher, in the
subsurface valley than the proposed Twin Pines workings. Because the water in
N,~4fU~ the sandstone aquifer and the water in the abandoned mine working9s flows
? downdip, water from the_ as~ter~ end of the Caldirola Mine could f]ow into the
Twin Pines No. 2 Mine, thus dowering the piezometric surface in the lower
pool. As found above, however, because the upper pool is entirely separated
from the lower pool, no impact to the water source in the upper pool is
anticipated. Also because the abandoned Caldirola Mine is updip of the
proposed workings and because water flows downdip, no qualitative impacts are
anticipated to the source of water to the Caldirola Mine. In the Division's
estimation there will be no impact to the water source which supplies the
upper pool in the abandoned Caldirola No. 2 Mine and therefore there will be
no impact to the water which supplies the Coal Creek water right.
In order to verify the preceding interpretation of the prevailing hydrologic
balance, the Division is proposing the following monitoring system. The State
Engineer in a memo dated Novemoer 30, 1983, concurred that the following
stipulations are necessary to ensure compliance. Should monitoring indicate
possible impacts to the water which supplies the water right, the Division
will require a plan in accordance with C.R.S. 1973, Section
34-33-111(2)(m)(III) which identifies sources of water which could be utilized
as supplementary water for the Caldirola i4ine well water right. The Division
deems the following stipulations necessary to conr'irm the predictions of
probable hydrologic consequences and to ensure that the perfiornance
requirements of Rule 4.05 will be met.