As the value of minerals continues to rise in the marketplace, mining companies are revisiting their heap leach pads.
A heap leach pad or dump leach can contain a wealth of minerals that are waiting to be discovered.
Precision Drilling Australia offers a unique solution with High Pressure cyanide injection well installations utilising numerous drilling techniques including sonic and other conventional drilling methods to sample and install wells into targeted heap leach pads.
Heap leach pads are large piles of rock waste from a mine operation that receive further processing through a leaching solution to remove the mineral ore from the rock.
The leaching solution is applied via an irrigation or sprinkler system to the top of the heap leach pad. The solution penetrates the heap leach pad and separates the mineral ore from the rocks.
At the bottom of the heap leach pad is an impermeable liner that is angled to allow the solution to be collected in a reservoir and then be sent for further processing.
First the Precision Drilling team needs to drill test holes to determine the depths of the dry zones and the specific lithological (physical characteristics of the ground) information with an estimation on how many grams per a ton is in the location.
Precision Drilling Australia can collect highly representative samples and achieve excellent sample recovery. Leach pads are made up mostly of unconsolidated material and the sonic drilling technique has proven effective in these conditions by producing 100 percent accurate in-situ core samples. The rig is also used to install wells in the heap leach pad.
Once the target zone is confirmed the next step is to proceed with the well installation in the leach pad and to install the cyanide injection wells, the wells have a perforated screen at the designed length set by client’s specifications.
The casings allow the borehole to stay intact, as an upper and lower k-packer are installed at specific depths to direct the cyanide solution at targeted areas and depths with in the borehole.
This process is repeated on an eight-week cycle with four weeks of solution and four weeks of rest. Once the cycle is completed, the k-packers inside the perforated screen are moved to a new depth. The well would receive the solution at three heights, targeting the bottom, middle, and top.
With experience in all aspects of Exploration, Geotechnical, Environmental drilling, and Hydro and Water Well Drilling, we are here to look after our clients in a professional, ethical, and reliable manner, while maintaining safe, environmentally responsible practices.
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