WorldWide Drilling Resource

Planned and Executed Adapted from Information by Albion Drilling Group Ltd Albion Drilling Group LTD was award- ed the design and build contract by Cuddy Group to assist in the enabling works of a housing development for Persimmon Homes in Plymstock, England, UK. The works included both presplit and bulk blasting within the old limestone quarry at Plymstock. Blasting was followed upwith bolting and meshing of both the previ- ously exposed west face, and the newly exposed north and south faces. To avoid possible difficulties in the sequencing of the works, Cuddy Group chose to combine both the blasting works and the stabi- lization works within the same contract. Blasting was primarily a large-scale cut and fill operation. The stone produced from bulk blasting was transferred from one end of the quarry to the other, rais- ing the quarry floor at its highest point by 50 feet above the initial ground level. Albion used two Atlas Copco D50 drill rigs to complete the blasting works. On the north face of the quarry, a newly exposed face was formed using presplit blasting techniques. The company was able to form a relatively stable face at the desired 80-degree inclination. Each blast was designed by the company’s on-site team of engineers, utilizing the latest available technology, to provide the best results in terms of fragmentation and efficiency. In total, there were 111 blasts from start to finish. During stabilization works, Albion used both roped access and long reach excavators to complete the required drilling works. The west face was stabilized first in just six weeks. Works on this section included the installation of over 1300 rock bolts together with rock fall netting. Works on the other two faces had to be completed over time as the new face areas were exposed. It was essential the blasting works were coordinated to a set sequence of lifts and lengths, allowing the stabilization works to take place before continuing with the next part of the excavation. In addition to the coordination of the drilling works, time was allowed for necessary design assessments to be completed prior to stabilization works commencing on the various sections. Albion executed a well-thought-out management approach to complete all of the various works throughout the project in a safe and efficient manner. The com- pany credits their team of highly skilled and dedicated employees for the project being finished on time. 23 WorldWide Drilling Resource ® OCTOBER 2018 EXB