Laserfiche WebLink
• <br />MINE ID #` OR PROSPECTING ID f <br />INSPECTION DATE 4/18/96 <br />(Page 2) • <br />K-94-117 <br />INSPECTOR'S INITIALS CBM <br />This was a monitoring inspection conducted in response to a telephone complaint received from <br />Bob l4ason, a resident of the Town of Gold Hill. Mr. Mason stated in the complaint that he <br />had observed the spray evaporation system in the tailing pond being operated in such a way <br />that process water from the tailing pond was being sprayed outside of the lined area. Mr. <br />Macon stated that spray of tailing pond water outside of the lined area was occurring as a <br />reeu:Lt of one of the main (2-inch) lines of the spray evaporation system being moved to a <br />location on or near the crest of the tailing dam. Operation of the spray evaporation system <br />in this configuration would be in conflict with a condition specified in the Division's <br />3/18/96 approval letter for the spray evaporation system. This condition ie restated here: <br />The Division will require that the spray heads be set-back from the pond <br />embankment such that the spray is wholly contained in the pond under <br />normally anticipated wind velocities. <br />At the time of this inspection, an appropriate set-back between the spray heads and the pond <br />embankment had been reestablished. Mr. Hartley and Mr. Fox stated that the condition Mr. <br />Mason observed, of spray occurring outside the lined area, was caused by a vandal or vandals. <br />it is the Division's position that the operator of the spray evaporation eyetem needs to <br />inspect the condition of the pipelines and spray heads prior to powering the pump, and needs <br />to c~egularly inspect the system while it is operating. Mismanagement of the spray <br />evaporation eyetem may result in an enforcement action being taken by the Division. <br />The ,spproved design for the spray evaporation eyetem specifies that a minimum of 64 spray <br />heads will be deployed in the pond. At the time of this inspection, there were 48 spray <br />head:a in the pond. At the time of the Division's 4/2/96 inspection, the operator had stated <br />that the main lines would be extended, and additional spray heads installed; the operator <br />further stated that the pump would be upgraded to a 250 gpm model (ae specified in the <br />approved design). In the Division's 4/2/96 inspection report, it is stated that "spray <br />evaporation within the lined area of the pond needs to be maximized." Based on observations <br />made during this inspection, the Division now finds that it ie necessary to apply enforceable <br />dead:Linee for the installation of the additional spray heads and the 250 gpm capacity pump. <br />A minimum of 64 spray heads must be installed and operational in the pond no later than <br />5/1/!)6. A pump that ie in good operating condition, and that ie rated to pump 250 gpm at the <br />minimum required net positive auction head, must be installed and operating no later than <br />5/1/96. See PB #1 on the last page of this report. <br />At the time of this inspection, only 9 of the 16 spray heads on the main line closer to the <br />upstream Bide of the pond were operational. The other 7 spray heads were plugged with <br />debr.ie. To correct this problem, the Division will require that the filter at the pump <br />intake be upgraded and properly maintained. The filter screen needs to be stapled to the <br />outside of the bracing box eo that it does not collapse around the pump intake as was <br />observed during this inspection. if the filter at the pump intake ie not properly maintained <br />and ]cept in good working order, the Division may take an enforcement action. In addition, <br />some spray heads on the main line near the embankment were submerged in the pond. The <br />Div iiaion will require that main lines be placed on a sufficient number of well braced pipe <br />etan<9e such that the spray heads are above the pond surface at all times. If submerged spray <br />headia are observed by the Division at any future inspections, an enforcement action may be <br />init:Lated. The spray heads must be kept clear of debris and in good working order. See Pe <br />#`2 oia the last page of this report. if spray head fouling continues to be a problem, the <br />Division will require that a more sophisticated pump intake filtration eyetem be devised, <br />also the Division may require that redundant spray evaporation lines be installed that are <br />valved such that the redundant lines can be operated independently of the existing lines. <br />Ae such, the redundant line could be operated while the primary eyetem ie being maintained. <br />It is the Division's position that the spray evaporation eyetem at the Gold Hill Mill moat <br />be operated with considerably more diligence than has been exhibited during the period <br />between the Division's 4/2/96 and 4/18/96 inspections. According to the projections in the <br />3/17/96 evaporation eyetem design by Richard Fox, the eyetem would have to be operated at 250 <br />gpm f:or from 31 to 66.5 hours to eliminate 20,000 gallons of process water. Based on these <br />projections, and on the potential ground water inflows to the Hazel-A outlined in the <br />Division's 2/27/96 letter, anything more than minimal down-time for the spray evaporation <br />