21 JULY 2022 WorldWide Drilling Resource® LOOKING FOR A GREAT DEAL? LOOK NO FURTHER! 850-547-0102 Blasthole Drilling and Mining by Ronald B. Peterson Drilling Products Specialist, Mountainland Supply Company Blasthole drilling is a method used in mining and quarrying, and sometimes in construction operations. It is carried out to break up rock and hard minerals, to make it easier for the mining crew to get to the resources being mined. The initial hole into which the explosives are packed is known as the “blasthole.” A hole is drilled into the surface of the rock, then loaded or packed with explosive material, and detonated. The aim of this technique is to induce cracks in the inner geology of the surrounding rock, to facilitate further drilling and associated mining activity. Blastholes are a fundamental step in the mining process, and can be employed in both surface mining operations and underground mining operations to varying degrees with varying effects or results. Mining engineers and planners will determine the most effective, efficient, and safest way to proceed, then the project manager will take over and draw up the necessary drilling plans. Once the blastholes have been drilled, they will be packed with explosives. The type and the amount of explosives used will have been determined based on the research conducted; just like the size and depth of the blasthole was determined based on the research. The explosives will then be detonated remotely to break up the rock. Once the exciting part is over, somebody has to stay behind and clean up the mess. In underground mining, the tunnel will be cleared of debris and suitably reinforced. Otherwise, as in open-mine blasting, the rock will be excavated and hauled. Surface blasthole drilling, for want of a better term, is production drilling on steroids. The rig is normally moved with the mast up. This is typically a nono in most drilling operations. The formations being drilled have typically been drilled and blasted previously; therefore, the formation is already broken and friable. Fortunately, the holes are usually relatively shallow, but they still have to remain open and stable long enough to pack the hole or place the charge. Blasthole drilling is a high-energy environment with high pressure and high-volume air. Formations that have been previously drilled and blasted tend to become even more unstable in this situation. One method often used to counter this issue is to drill the holes using a drilling foam. Foam can be enhanced by adding a polymer, creating a stiff foam which can further stabilize the hole. The use of foam and stiff foam reduces the amount of air required to clean the hole and helps keep the hole open. Working together, it is amazing where we can go. Enjoy the trip! If you have any questions on drilling fluids or another topic you would like addressed, please remember this column is ours. Help me make it of value to you. It needs to be an interactive tool - I need your feedback. Contact Michele (below) and she will get them to me. Ron Ron Peterson may be contacted via e-mail to michele@worldwidedrillingresource.com EXB from WWDR and DBGD
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