Blasting, fragmentation and wall quality result at West Wanagon slope stability project on Grasberg Mine

[摘要] West Wanagon Slope Stability (WWSS) Project is part of final slope design of Wanagon OBS in Grasberg District, which provide around 150 Mton of Limestone as rock fill material, slope protection cover, drainage riprap layer and rock drain system. The design will balance operating objective with effective environmental, safety controls, geotechnical stable, adequate drainage with minimum erosion and facilitate revegetation. For past 3 year, PTFI has developed WWSS Geology Rock Model to identify various geology feature to lead blasting pattern and timing design to achieve fragmentation requirement and final slope quality. On 2017, there are 75 vibration monitoring data and give a result of blasting constant PPV = 137.63 SD^-0.899. This is based on pattern 7m x 8m with timing 62 ms x 89 ms (74%), 49 ms x 96 ms (13%), 62 ms x 110 ms (5%), 46 ms x 50 ms (3%), 46 ms x 86 ms (3%) and other (2%). The result of blasting on slope wall quality using modified - controlled blast evaluation chart (Read and Stacey, 2009) is able to achieve 1. Good Result = 69.2%, 2. Geometry Achieved=3.8%, 3. Good Face Condition = 23.1% and 4. Unacceptable result = 3.9%. The fragmentation has taken at various location and has result that D50 = 174 mm, which meet slope cover requirement with screen to reduce fines content.

[发布机构] PT Freeport Indonesia, Indonesia^1

[效力级别] 矿业工程

[关键词] Evaluation charts;Fines content;Geotechnical;Rock fill materials;Rock models;Safety controls;Slope design;Vibration monitoring