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2) Background <br />mine portal was in in 2008-09. The mine portal collapseder site remedial activities were completed. n the first quarter of 1009. <br />The p <br />Portal repair activities were addressed whenoth professional ge ogi t was retained to provide a site <br />March of 2011, Dr. Gonzales a cert <br />reconnaissance assessment (Attachment 1) to determine the cause � n h and portal area nd eect of the al <br />2011 <br />collapse. Mountain Man Surveying surveyed the May Day Mortal and bench geotechnical <br />and again in 2016 (Figure 1 "As -Built" Drawing). In 2011, p <br />characterization was conduct by R Squared, Inc. (AttachmentDRSttechndal revisionother r(TR) acts were The <br />initiated to develop a portal stabilization plan and a <br />retained contractors included: <br />R Squared, Inc.; (Bench Geotechnical Characterization); <br />Mountain Man Surveying: (Map Base and As -built Preparation); <br />• Manhard Engineers; (Technical Revision Development); <br />• EnviroGroup, Limited; (Technical Revision Development); <br />Trautner Geotechnical, LLC (geotechnical engineers); <br />Franklin Drilling and Blasting, In. (Rock Bolt, <br />Mesh and Headwall Stabilization); and <br />• Melcher Brothers (Portal Set Design and Construction <br />4 <br />3) Approach <br />Project activities; <br />• Reviewed site aerial photographs; <br />• nch geotechnical data (Attachment 2); <br />Reviewed and assessed historical be <br />Received CDRMS —Technical Revision Approval (Attachment 3); <br />• Conducted field slope measurements; Collected information to finalize rock anchor <br />installation and foundation and head wall geotechnical testing; potential tension <br />Hand excavated tests holes above and blow the could influence portalall; to dinstability; fy p <br />cracks and other conditions tha <br />Obtained laboratory testing soil and rock material for engineering analysis; <br />Reviewed foundation moisture characteristics, <br />• Conducted the following analytical tests including: <br />o Moisture content and dry density; <br />o Atterberg Limits used for general classifications; <br />o Sieve analysis tests to assess the drain distribution of the samples tested; and <br />o Direct shear test to assess strength characteristics; <br />• Observed cut slope excavations to confirm the slope inclinations and material <br />physical construction characteristics. <br />Wildcat Mining Corporation <br />May Day and Idaho Mine and Mill Application <br />112(d) Permit — Technical Revision No. 1 <br />May Day and Idaho Mine <br />M-1981-185 <br />Revised June 30th, 2016 <br />