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Spotlight

Reverse Circulation Drilling

Mon, 10/21/2013 - 21:04

Mining and exploration companies often prefer Reverse Circulation (RC) drilling to Diamond Core, due to the fact that RC drills provide approximately twice the sample size and speed rate at approximately half the cost of core drilling; in most cases RC also delivers 100% of the sample, whereas core drilling sometimes cannot. It is often essential for companies to receive the complete sample. For example, in the cases of coarse, nuggety gold, or very fine grain gold flakes that are loosely held along fractures and which can be washed away with drilling fluids or water, it is often difficult to make an accurate grade evaluation using Core Drilling. In these cases RC is the preferred drilling method, due to the larger sample size and complete sample recovery that it provides.

Because traditional RC drill rigs tend to require a large footprint of up to 20x20m, this often limits the options for mining and exploration companies as well as adding to the cost of expensive road and drill pad construction, along with creating additional issues with the government and property owners relating to the potential negative environmental impact.

Globexplore Drilling has worked with its rig builders in the US and Canada to design a series of RC rigs with footprints as small as 6x8m that solve these problems. This new series of drill rigs offers the same high power capacity as the more traditional truck-mounted rigs, yet they are roughly half their size, as well as being equipped with a host of modern technology features, such as automated rod loaders and remote control operations. Globexplore has two self-propelled Track- and Buggy-Mounted rigs, both of which can turn in a complete circle within their own footprint, allowing quick moves between holes. The rig tows a separate air compressor, which can be run up to 150m from the rig on a separate pad or at a different elevation, for example. The company also recommends running the compressor as a separate, replaceable component to the rig, because mechanical failure on that component is the most common cause of downtime. “If a compressor goes down we can swap it out and have the rig back up and drilling in a couple of hours,” says Armando Lucero, RC Operations Manager at Globexplore.

The small size of the rigs offers a powerful solution for companies looking to capture 100% of their sample from the surface or from underground applications in a safe, quick and economical way, while minimizing the environmental impact of RC drilling.