Laserfiche WebLink
ACZ <br />Ms. Cathy Begej <br />January 14, 1992 <br />Page 6 <br />The static factor of safety required by Rule 4.10.4(2) is 1.5. Based on the above results, the existing and <br />planned refuse pile configuration at the Southfield Mine will meet regulatory factor of safety requirements. <br />4.0 Conclusions and Recommendations <br />The above stability analyses were based on data obtained from previous studies conducted for Southfield and <br />reported construction practices for the refuse pile. The critical parameters in the stability analyses are [he <br />assumed strength properties of the refuse material and the groundwater levels within the refuse pile. We <br />understand [hat an underdrain system has been installed at the base of [he pile to control the buildup of water <br />levels. To date, the system appears to be performing well and there are no reports of seeps on the exterior <br />slopes. <br />The strength parameters used for [he fine refuse material in [he stability analyses indicated a frictional material. <br />The values used arc typical for non-plastic granular material. We understand that there is some variation in <br />the characteristics of the coarse and fine refuse depending on normal changes in [he geology and mining <br />practices. Therefore, it may be prudent to sample and [es[ plasticity characteristics of the fine refuse to identify <br />an acceptable range. If high clay content material is encountered in the mining operations, it could be sampled <br />and compared with this range, with selective placement in the pile to avoid adverse stability impacts if high <br />plasticity is indicated. <br />5.0 Use of Report <br />This report has been prepared for the exclusive use of [he Southfield Mine for specific application [o [his <br />project. Within the limits of the schedule and budge[ for our work, [his study has been performed in general <br />accordance with locally accepted geotechnical engineering practice [o provide information for [his site. <br />Assumptions relative [o subsurface conditions at [he site were based on previous reports supplied by Southfield. <br />The subsurface conditions in [he portions of the site [ha[ were not sampled could vary from [he conditions <br />observed in [he borings supplied by Southfield. In addition, variations in [he surface conditions between the <br />borings and in [he groundwater conditions with time are possible. <br />We hope this meets your needs. If you have any questions or require any additional information, please contact <br />us. <br />Sincerely, <br />ACZ Inc. <br />Patrick Corser, P.E. <br />Principal <br />J ry N ton <br />Senio ngtneer <br />PGQksp <br />attachments <br />