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George V. Patterson, Energy Fuels Coal, Inc. <br />Page 11 <br />February 12, 2015 <br />and at atmospheric pressure (at least in the vicinity of MWNW) since MWNW is not sealed. <br />Therefore the local groundwater flow direction from these two monitoring points is probably <br />towards the mine. MW16 has been reported as dry, although the level indicated as dry is higher <br />than previously recorded water levels, so further clarification is necessary. Using these two (or, if <br />MW 16 can be clarified, three) data points alone it is not possible to make any meaningful <br />assessment of the rate at which the mine workings are filling with water and the local hydrologic <br />balance is returning to equilibrium. <br />In the 2013 Summary Report9 BBA attempted to model the refilling of the mine using: (i) an <br />estimate of the volume of the mine cavity, and (ii) estimated volumetric rates of mine inflow; <br />with three different scenarios of hydrogeologic connectivity within the workings. The report <br />concluded that the time for the water level in the mine to reach 5860.5' would be 106 -200 years. <br />There is significant uncertainty associated with the values of all of the input parameters for this <br />calculation, for example: <br />• There is confusion about the lowest elevation that could be measured at MWNW. <br />There is uncertainty about the extent to which the mine cavity has collapsed, which has <br />implications for the volume of the remaining cavity. The 5,700 Acre feet value quoted <br />from page 2.05.6 -32 is a maximum value for the volume of the cavity, taking no account <br />of subsidence or natural caving. <br />The mine inflow volumes (summarized in table 1) are quoted to a level of precision that <br />gives a misleading impression of the accuracy of the value. Since it remains unclear how <br />the estimates were made there can be very little confidence in these values. <br />As acknowledged by BBA, the integrity of the seals within the mine workings is <br />unknown. <br />The ideal location for a well to monitor the rate at which the mine is refilling and the quality of <br />water in the cavity would be at a lower elevation of the mine cavity, perhaps in the West Submain <br />or 2 West Submain, (drill holes SR14 and SR61 would be well located). However the North <br />Dewatering Well was converted to MWNW with TR35 in 2003 for this purpose. MWNW has <br />been described as a monitoring well throughout the PAP and other documents, which is <br />inaccurate; really it is simply a cased hole, open to the mine workings. Nevertheless, and as stated <br />on page 2.05.6 -53, the purpose of this monitoring point is to: <br />"...track progressive mine flooding, water levels and water quality." <br />On page 2.05.641 the mine inflow rate is estimated as 330 Acre feet per year. Using the <br />previously quoted figure of 5,700 Acre feet as the maximum volume of the mine cavity, the mine <br />would be expected to refill completely in 17 years. It is noted that the analysis of BBA suggests <br />that the rate of mine inflow was overestimated. Without a data point in the mine workings none of <br />the assumptions that underlie any of the estimates or models can be verified, and the rate at which <br />the mine is refilling will remain a matter of conjecture. <br />i) Please provide monitoring data from MWNW, in accordance with the approved water <br />