The contractor needed to remove various sized in situ rocks that were located beside an active penstock. Completed in September 2017.
Scope of Project
The in situ rocks that had to be removed were directly on an active stream line. Water surrounding the rocks had to be pumped out to allow for drilling and loading. The narrowness of the stream and the position of various sizes of in situ rocks created a situation where a rock breaking machine could not operate. Rock removal had to be completed near an active penstock which was within 3 ft of where the blasting occurred. A low impact explosive was required to ensure not to damage equipment, materials, and existing site infrastructure.
Which GeoBreak Products Were Recommended
The in situ rocks that needed to be removed ranged between 0.05 cubic meters to 0.896 cubic meters. With this range of rock size, the products recommended were 34mm Nxburst™ cartridges with weight charges between 20g to 250g.
The expected outcome was to break the rock into manageable size pieces. A crew of workers could then hand remove the rock or machine excavate the blasted rock debris.
The contractor used approximately 20-25, 34mm Nxburst™ cartridges which fragmented the rocks into manageable size pieces. A crew of workers could then remove the debris by hand, allowing for quick transitions and no delays between each blast.
Final Thoughts From Project Contractors
Using Nxburst™ cartridges saved the client both time and money because of its precision and ease of use. Compared to traditional high explosives, Nxburst™ cartridges do not create high vibrations, unstable shock waves or a high level of flyrock. The sensitive nature of the product ensures minimal impact, which aids in the protection of existing infrastructure onsite. During the rock removal process, Nxburst™ cartridges prevented damage to the penstock or onsite equipment. Due to the adverse locations of the in situ rocks that needed to be broken, a handheld pneumatic drill was the only piece of equipment that could have be used to drill the appropriate holes for the loading process.