The Evolution of Technology in Open Pit Mining
From different explosive compounds to blast tubes and borehole liners, the mining industry is constantly changing.
Since their invention in the late 1970s, blast hole liners or blast tubes have been an integral part of the open-pit mining process. Blast tubes allow for mining in previously impossible locations. Not only has this invention opened new possibilities in areas previously incompatible with blasting, but it also helps achieve more consistent detonations.
Achieving a quality blast is imperative in keeping the rest of the costs of mining down.
An in-depth breakdown in the book Rotary Drilling and Blasting in Large Surface Mines, explains that blasting equates to roughly 15% of the cost of mining. Beyond the initial cost, the quality of the blast directly affects the cost and efficiency of the later steps in the mining process." Gokhale Because of the importance of a quality blast, many innovations have come since the 70s, utilizing different styles of explosives and varying types of liners.
Mining practices continue to evolve to meet the conditions of the environment.
The most commonly used explosive over the last several decades has been ammonium nitrate fuel oil (ANFO), which was discovered in 1867, and first used in 1955. ANFO is an affordable explosive but requires a dry environment. As a result, some mining companies opt to use blast casings or tubes made from PVC, which is a fantastic solution for keeping materials dry but can be dangerous due to the risk of static electricity. Additionally, "anti-static" borehole liners can be used in conjunction with PVC tubes to reduce the risk when loading the charge. However, these anti-static sleeves come at an additional cost.
Since the invention of ANFO, chemists have developed newer explosive mixtures more conducive to wet conditions.
In recent years, recycled cardboard blast casings have been utilized with great success since the development of emulsion-based explosives allowing companies to cut down on the plastic products they consume. While the primary advantage of pure ANFO is affordability, Emulsion blasting is water-resistant, unlike ANFO, and therefore doesn't require the borehole to be lined in plastic.
While straight ammonium nitrate emulsions provide the most water resistance, there are a few drawbacks. The first is cost, and the other is that pure ANFO still provides a better blast in most mining operations. This quandary led to the invention of emulsion blends ANFO and emulsion blends. According to Pit&Quarry, a ratio of 2:3 emulsion to ANFO is enough to achieve water resistance. This cuts down on cost while still providing a water-friendly solution with a high-quality blast.
Designing paper blast casings that work.
Even when using emulsion or emulsion mixtures in wet environments, the blast hole casing must still maintain shape throughout the process. Water rapidly degrades the structure of paper tubes. Therefore, the tubes must undergo a special treatment process to withstand being submerged in water. The standard solution has been to coat the tubes in paraffin wax to increase water resistance. It's a messy, time-consuming process. Engineers at Erdie Industries have developed the next generation of blast tubes that can last much longer in wet environments compared to wax-coated competitors.
Moving forward with new mining products for a greener future.
The new Dirty Erdie Blasting Tubes, made right in Lorain, Ohio, are made from 100% biodegradable, environmentally-friendly paperboard. Our mission is to create value through the innovation of world-class products and service while remaining sustainable and customer-driven.