Laserfiche WebLink
VI. SUMMARY AND CONCLUSIONS <br />Development of Aggregate Industries' Morrison Quarry appears to continue in general <br />accordance with the approved Mine Plan. Mining is continuing in the North Quarry and is <br />complete in the Central Quarry. Mining is in accordance with the Observational Method <br />presented and approved in the permit amendments and technical revisions. Mining in the North <br />Quarry has varied slightly from the phasing presented in Amendments Nos. 4 and 5 to improve <br />operational considerations and to provide for adequate mining safety for personnel, but has not <br />varied from the planned ultimate build out. Mining in the Central Quarry has completed within <br />the approved mining limits presented in Technical Revision No. 3. <br />In the Central quarry, the overall slope of the east side of the quarry did not exhibit visible <br />instabi]ity. Localized instabilities exist on individual benches. Moderately dipping foliation <br />jointing combined with other continuous joints has created localized slip surfaces that have <br />resulted in lost of portions of individual benches and non-vertical highwalls during mining, and <br />the potential for other localized losses in the future. The overall slopes on the west side, and <br />north and south ends did not exhibit visible instability. On the east side of the Central Quarry, <br />the repaired slope remained stable based on periodic optical survey monitoring. <br />In the North Quarry, a final highwall appeared completed on the north side of the quarry above <br />Bench 1. This bench and highwall appears to be excavated steeper than 1H:1 V, with highwalls <br />generally no higher than 50 ft. Current mine slopes are presently being excavated steeper than <br />1H:1 V, with highwalls generally no higher than 50 ft. The overall slope of the northern and <br />western sides of the quarry did not exhibit visible instability. Localized instability exists on <br />individual benches. The rock mass in the North Quarry is in "competent" condition, with a <br />localized "poor" conditions located in a zone of shearing and faulting. <br />