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PERMIT#: M-2009-076 <br /> INSPECTOR'S INITIALS: MAC <br /> INSPECTION DATE:November 19,2015 <br /> into the impoundment. Processing of waste rock last occurred in 2013. The tailings impoundment is one of <br /> several environmental protection facilities (EPF) at the site and was specifically designed and engineered to <br /> contain tailings capable of generating acid drainage. In accordance with Hard Rock Rule 7.3.1(4) and 7.3.2, the <br /> Division accepted the certification of the lined tailings impoundment and authorized the Operator to place mill <br /> tailings (acid-forming materials) onto the liner. <br /> Hydrologic Balance: <br /> Groundwater in the vicinity of the Hukill Gulch Millsite is protected through practice-based measures such as <br /> the composite liner system used in the tailings impoundment. Groundwater is monitored quarterly in up- <br /> gradient and down-gradient monitoring wells. The down-gradient well was installed in order to detect any <br /> leaks or seepage from the tailings impoundment. Both of the wells were visited during the inspection. The <br /> wells have been completed down to bedrock at an approximate depth of 20 ft. and consist of 2 inch HDPE <br /> pipes. The HDPE pipes extend above the ground surface approximately 6 ft. The above ground portion of both <br /> wells was bent over at an approximate 45 degree angle. The Division is concerned that the configuration of <br /> the HDPE pipes make them susceptible to damage. In addition, it is unlikely the Operator would be able to <br /> obtain a groundwater sample from the wells at the existing angle. The HDPE pipes should be secured in a <br /> vertical configuration using t-posts or some other type of brace. During the inspection, the Operator described <br /> the sampling process used to determine if there is water in the well and the process for collecting a <br /> groundwater sample. The process described by the Operator does not conform to the approved groundwater <br /> sampling plan. A copy of the approved groundwater sampling plan has been attached to this report for the <br /> Operator's reference. The observed condition of the monitoring wells and the Operator's sampling method <br /> have been cited as a problem and will require corrective action by the Operator. Please see the first page of <br /> this report for additional information. <br /> Gen. Compliance with Mine Plan and Reclamation Plan: <br /> The purpose of this inspection was to follow-up on the Division's previous site visit conducted on September <br /> 15, 2015. During the last inspection, the Division observed that the Operator had placed mine dump materials <br /> onto the tailings impoundment liner. Mr. Maher informed the Division that he observed noticeable <br /> weathering of the exposed portion of the liner. In order to protect the liner from further weathering, the liner <br /> was covered with on-site material including country rock, mine dump material and soil. The material placed <br /> onto the liner consisted of large angular pieces of rock up to 24 inches in diameter.The material which was <br /> placed onto the liner was excavated from the historic mine dump located immediately above the first bench of <br /> the tailings impoundment. In addition to large angular pieces of rock, the Division observed pieces of timber <br /> and metal debris within the tailings impoundment. The timber which was observed on the liner was also <br /> evident in the mine dump. Historic mining structures previously present on the site were likely the source of <br /> the timbers. The timbers which were visible ranged from 2 ft. to 6 ft. in length. The Division did not observe <br /> nails in any of the timbers. However, when the historic mining structures were dismantled and placed into <br /> mine dumps, little effort may have occurred to removing nails from the timbers. <br /> As noted above, the tailings impoundment was designed to hold the fine-grained sand which is produced from <br /> processing waste rock. The analysis of the tailings impoundment design took into account a variety of factors <br /> such as seismic resistance, phreatic surface control, particle size distribution, hydraulic conductivity, strength <br /> property testing of the tailings, as well as interface friction testing and pressure testing of the composite liner <br /> system. The act of placing mine dump materials onto the liner as well as the method of placement was not <br /> accounted for in any of the performed analyses and the Division cannot be certain if the liner is fully intact. As <br /> a result, the certification for the EPF is void and it may no longer be used for its intended purpose. <br /> Page 3 of 9 <br />