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2013-07-26_REVISION - C1981014 (2)
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2013-07-26_REVISION - C1981014 (2)
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Last modified
8/24/2016 5:22:56 PM
Creation date
7/29/2013 1:30:21 PM
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Template:
DRMS Permit Index
Permit No
C1981014
IBM Index Class Name
REVISION
Doc Date
7/26/2013
Doc Name
2nd Submittal Change Request for Monitoring Well MW-NW
From
Energy Fuels Coal Inc
To
DRMS
Type & Sequence
TR40
Email Name
JHB
DIH
Media Type
D
Archive
No
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A summary of BBA's work (the "BBA Summary Report') and their support data is contained in Appendix <br />A included in this submittal. <br />BBA has concluded that the information necessary to provide sufficient data to evaluate the potential <br />impacts on the groundwater regime at Southfield is provided by the information available from <br />monitoring wells MW -23, being up gradient from the mine workings, and MW -65, being down gradient <br />from the mine workings. Specifically, the information available from these Wells provides information <br />regarding water level changes in the coal seams resulting from dewatering of the mine as well as <br />providing groundwater quality data. <br />In support of their conclusion, BBA noted that the Annual Hydrology Reports (AHR's) water levels in <br />MW -23 and MW -65 dropped 70 feet and 40 feet, respectively, when mining and dewatering activities <br />began. Considering this with the other data available for the groundwater regime at Southfield, BBA <br />concluded that the two wells are hydrogeologicly connected to the mine workings. <br />Further, the water levels have not recovered in the two wells at this time, approximately 15 years after <br />dewatering activities have ceased. As stated in the BBA Summary Report, this result is expected due to <br />the low hydraulic conductivity and limited horizontal contiguity of the Vermejo Formation and the coal <br />seams at this location. This continued trend of repressed water levels in the monitoring wells supports the <br />slow rate of inflow into the mine which had been predicted, observed and recorded. <br />The Bishop - Brogden work includes the results of three conceptual models that test whether MW -NW or <br />another well in that location is necessary to address the required criteria for the Southfield mine's <br />groundwater monitoring program. Importantly, the models run by BBA use actual inflow data for the <br />mine for the period referenced in the review. <br />Conceptual Model No. 1 <br />Conceptual Model No.I assumes that the entire mine is hydrogeologicly connected and refills as a single <br />unit. The results of the model demonstrates that it would take approximately 120 years after the year 2000 <br />for the water level to reach the identified monitoring point elevation of 5,860.5 feet (intake at bottom of <br />well). <br />Conceptual Model No. 2 <br />Conceptual Model No. 2 assumes that the mine seals around the 1St North, 1 '/2 and 2 North mine sections <br />are water tight and these areas refill as a unit separate from the rest of the mine. This model demonstrates <br />that it would take approximately 8 years, or by 2008, for the water level to reach the monitoring point <br />elevation (5,860.5 ft) and approximately 11 years, or by 2011, for the water level to reach the partial <br />obstruction's elevation at 5,879.7 feet. Accordingly, one would expect water to be above the partial <br />obstruction point (5,879.7 ft) if this conceptual model was valid. <br />Having previously proved by means of the water test April 17, 2012 in MW -NW that this well is in <br />connection with the mine workings, the lack of water in the well at the level of the obstruction shows that <br />this area is not filling separately from the rest of the mine as water would be observed in the well. <br />2 <br />
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