thyssenkrupp
Comminution accounts for over 53% of mine site energy consumption, which leads to the questions how do we make it more efficient and self-sustaining?

thyssenkrupp not only offers efficient comminution solutions for the mining sector, but also spearheads the inclusion of renewable power generation and storage solutions to reduce overall energy costs.

Efficient comminution

thyssenkrupp minerals processing GM Dr Wilfred Barkhuizen discusses the company’s minerals processing portfolio, noting that in addition to mills, high pressure grinding rolls (HPGRs) and lab automation, it now includes crushing and screening as well as the pilot of energy generation and storage solutions.

Crushing

The local mining client base is probably less familiar with the crushing element of the business but it is a strong focus moving forward across the sub-Saharan Africa territory.

Depreciating ore bodies require clients to crush and grind lower grade ores, presenting them with the additional challenge of crushing and grinding larger volumes. The result is seeing additional emphasis placed on ensuring we can deliver products and processes which are as efficient as possible with less operating costs.

thyssenkrupp has sold almost 50 primary gyratory crushers (largely semi-mobile installations) worldwide in the last eight years. The last semi-mobile primary gyratory crushers were sold to a Zambian copper mine and are in operation since 2015.

Along with the need for higher throughput crushers, more of the industry is looking to semi-mobile units, as they offer numerous production and cost saving advantages. Mobile crushers (even large primary gyratory ones) can be disassembled, relocated and prepared for pre-erection at a different location in the mine at shorter space of time.

Ours are manufactured in large, easy-to-assemble portions and because they are modular, installation and commissioning time is drastically reduced. The biggest benefit however is the small amount of civil preparation required, which includes ground compacting and retaining wall preparation. This reduces the overall costs associated with crushing substantially and adding the additional benefit of semi-mobility.

Alongside the growing trend for semi-mobile machines, there is a significant increase in interest for underground crushers. Crushing underground gives more capacity to skips, thereby assisting with high volumes and productivity.

Our Jaw and Gyratory crushers are customised to be easily transported and assembled underground. Instead of welded assemblies, they can be bolted together making them easy to transport to an underground location.

Broadly speaking, thyssenkrupp offers an extensive range of crushers, both in fully-mobile, semi-mobile and fixed, included in the range, hammer, single toggle jaw in a standard and heavy duty range, double toggle jaw, cone crushers etc. and its unique jaw gyratory crusher which allows clients to feed through large rocks, up to 3 m in size (ideal for block caving mining methods). It has a significant reduction ratio, again meeting the needs for high throughputs and difficult ores. Our roll crushers are also the largest in industry, capable of up to 14 000 tph throughputs.

New and innovative in-pit crushing and conveying

thyssenkrupp has developed a concept design for a new integrated in-pit crushing and skip conveying system, ideally suited to opencast mines. The system is based on existing underground technology and is designed to eliminate or reduce the number of trucks transporting ore from the pit to the plant. This will cut diesel costs significantly or entirely while increasing productivity.

The design includes a 250 m high skip conveying system connecting the pit to a higher level or to surface and can accommodate 8 000 tph. We are in discussions with various clients who are interested in testing the system which will assist us to further evaluate realistically the operating expenditure difference in comparison to conventional trucking costs.

Milling

thyssenkrupp has and continues to be at the forefront of milling technology, especially shell-supported mills.

The shell supporting structure is unlike any other mill on the market. Hydrodynamic bearings on the mill shell (as opposed to Trunnions) ensure effective load distribution  and with manufactured end walls (as opposed to castings) drastically reduce the risks and time associated with mill shell manufacturing and our unique dual pinion drive system transfers power more efficiently.

Apart from also offering Gearless Mill Drive solutions on the larger mills, the conceptual Multiflex Drive system, which utilises 4 drive systems can be offered as a more economical alternative with the added reliability benefit.

One of the thyssenkrupp developments is field welded shells which are becoming increasingly more popular due to the larger mill sizes and the associated logistic challenges.

HPGRs

The company is always looking at innovative applications where it can create highly effective minerals processing systems that are more energy efficient and also address the scarce water resources. We more specifically believe our HPGRs can be used in dry fine grinding applications and we are investigating this extensively.

The reality is that an HPGR can deliver between 30 and 50% greater efficiency in a fine grinding application as opposed to some of the conventional grinding circuits.

Quality control and automation

In all crushing and grinding processes, sample analysis is one of the most important prerequisites, not only for quality assurance, but also to control and adjust the processes constantly for optimum efficiency.

To this end we have just added further robotic innovation to our automated laboratory systems for the South African market. The Polab shuttle system adds unique flexibility to the laboratory environment in that it can be fully automated and integrated into plant control systems, and still allow manual operation.

Sample transfer by means of a mobile robot allows an unlimited freedom in terms of many configurations which can be extended to specific requirements. Individual modules such as a receiving station, sample preparation, input and output magazines and analysers are interconnected by a rail system on which the robot moves. A unique safety concept allows the laboratory to be used by humans which the robot is working, something which was not possible in the past.

At the end of the day, we all strive to bring innovation to the table to make life for our customers easier and as cost effective as possible.

For more information please contact:

Dr. Wilfred Barkhuizen - General Manager: Mineral Processing, Power & Energy

Wilfred.barkhuizen@thyssenkrupp.com

011 236 1318

All images from thyssenkrupp