“We have some major customers with very interesting projects in this sector,” explains Andrea Prevedello. This most certainly includes Prairie Eagle Mine in Illinois, the largest coal mine of Knight Hawk Coal. This is one of the most efficient underground mining
Management was looking for a more sustainable operating solution. “We provided an overland conveyor that transports the coal from the mine to the main processing plant,” describes Andrea Prevedello. “Our conveyor helps the company to considerably reduce its ecological footprint. With this technology, Knight Hawk can significantly reduce its long-term environmental impact compared to using truck transportation.” BEUMER Group not only supplied the conveying solution. As a system supplier, the company also supported the mining group in building a stockpile for hard coal. “The requirements for storing coal are obviously very different from other materials,” explains Andrea Prevedello. Some of the important requirements are changing if the stockpile is covered and if explosion-proof specific equipment is needed. Hard coal is very susceptible to spontaneous combustion, which is why the height of the stockpile must be in certain cases limited.
Circular or longitudinal stockpile?
It depends on the method
The stacking method of choice depends on whether the bulk material is only temporarily stored or if it also needs to be blended. “For simple stockpiling without blending, we provided with the simple ’cone shell method’,” describes Andrea Prevedello. The stacker only moves up and down, not slew. The stacker design can be more simpler. This method works for longitudinal as well as circular stockpiles. For blending the bulk material however, the Chevron method can be used. The boom of the stacker starts in its lowest position. The first row is deposited in the centre of the stockpile, the next rows are layered on it. In longitudinal stockpiles, the stacker usually moves in a tilting and slewing motion, in circular stockpiles the stacker moves in a circulating and luffing motion.
Efficient coal mining
“The perfect system solution is always an optimal relation between stacker and reclaimer,” explains Andrea Prevedello. Reclaimers such as side reclaimers or bucket wheel remove the material, as necessary. The best option for the customer depends again on the stockpiling task at end. Side reclaimers work for both types of stockpiles, longitudinal or circular. The bulk material can be reclaimed from the front or the side. When reclaiming from the side, scraper chains move the material on a belt conveyor. Front reclaiming usually uses a rake that in small side-to-side movements pushes the material on a scraper chain to be transported further to the conveyor. The advantage is that the bulk material is reclaimed from the entire cross-sectional area. Bucket wheel are used in particular when the bulk material, especially in large quantities, needs to be blended.
Each operator has their own very specific requirements on the stockpile and stockyard machines. This is shown in a project that the BEUMER engineers are currently implementing for a customer in the energy industry. The order includes the delivery of several conveyors, including Pipe Conveyors, and a ship loader. The challenge: “On the ground where we will install our solution, there can be violent gusts of wind,” reports Andrea Prevedello. “That’s why we pay special attention to the dimensioning of the steel structure.” The system provider will thus be able to hand over a tailor-made system to the customer, with investment expenditure tailored precisely to him. The expected commissioning is scheduled for the third quarter of 2020.