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5 ' <br />f <br />George Patterson <br />May 30, 2014 <br />Page 2 <br />During the recent 2014 test, the 1,500 gallons of water were introduced to the well in less than 13 <br />minutes. Accordingly, water was introduced to the well structure at rates of approximately 115 <br />gallons per minute. It was observed during the test that all of the water, except for a small amount <br />spilled at the surface, entered the well structure without overtopping the well casing at the surface. <br />The well test observations indicate that water was entering the mine workings at a rate of somewhere <br />between approximately 74 and 115 gallons per minute. <br />The observed inflow rates through the MW -NW well structure indicate that the well is still in good <br />connection with the mine workings. The geologic material adjacent to the mine is significantly low <br />in permeability, such that the adjacent geologic material would not have received water at the <br />observed flow rates. Accordingly, the introduced water must be flowing into the mine workings <br />which are in connection with the well. <br />As presented in previous reviews of the MW -NW well and the Southfield Mine, mine inflow rates <br />are on the order of 10 to 20 acre -feet per year or approximately 6.2 to 12.4 gallons per minute, <br />significantly less than the tested rates. Due to the low rate of mine inflow, only a small amount of <br />connection with the mine workings would be required to allow for the monitoring well to provide <br />accurate water levels for the mine. The tested rate is over 10 times the expected mine inflow and <br />will allow for accurate water level monitoring. <br />Summary <br />Based on the 2014 confirmation of the connection between the MW -NW well and mine workings <br />originally indicated by the 2012 test, it is our opinion that the MW -NW monitoring well is still in <br />connection with the mine workings and that the level of connection is sufficient to allow for an <br />accurate reflection of conditions in the mine workings. It is our opinion that the MW -NW <br />monitoring wells still functions adequately as a monitoring well for the Southfield Mine. <br />We hope this letter has addressed the potential connection of the MW -NW monitoring well with the <br />Southfield Mine workings and suitability of the well structure for monitoring water levels in the <br />mine. If you have any questions or need additional information, please do not hesitate to contact us. <br />Very truly yours, <br />BISHOP - BROGDEN ASSOCIATES, INC. <br />I a <br />Timothy A. Crawford, P.G. <br />Project Manager /Hydrogeologist <br />TAC /j eb <br />Enclosures <br />2018.04 <br />www.bbawater.com <br />