Mine Support Products (MSP) has improved the testing capabilities of its ground-breaking onsite dynamic testing facility by adding a new horizontal press to complement the existing vertical press to ensure that the company’s products go beyond the standards required for underground support systems.
MSP’s revolutionary dynamic testing facility, which is the only facility of its kind in the Southern Hemisphere, was officially launched by the company in late 2013. It initially consisted of a vertical press that is able to simulate underground seismic activity by testing static loads of up to 100 tons and dynamic loads of 40 tons at 3-meters-per-second.
MSP general manager Conrad Engelbrecht reveals that the inclusion of a horizontal press allows for a greater degree of product testing on its tendon support systems, such as the Rocbolt, and the new shredder bolt system – a unique underground support system that acts as a friction bolt that can be used with cement, with the capabilities of an end anchor and yielding under dynamic loads, thanks to a patented the end mixing cone at the end of the bolt.
It also allows for improved testing on Rocprop MK1 – an all-steel elongated support system with predictable and repeated performance, catering for static and dynamic load conditions and ensuring availability of the excavation for its lifespan.
“Rocprop units are able to extend up to 6 m in height. In the past, however, the vertical press was limited to test units up to 4.2 m in height. The horizontal press now ensures that we can test the Rocbolt units more accurately, and provides the added benefit of undertaking side load testing of up to ten tons, as well as pull testing on tendons and bolts,” explains Engelbrecht.
Under static load conditions, Rocprop is able to sustain constant load-bearing characteristics during blasting, and maintains the integrity of the hanging roof during closure. In both static conditions and in seismically active mines, it provides a constant resistance to keep loose blocks in place.
According to Engelbrecht, the horizontal press features a 200 ton load cell, which enables the company to undertake pull tests up to 40 tons, and compression tests up to 120 tons. “The pull test can be undertaken according to proof load or to point of destruction.
“MSP’s Tendon support can now be tested and load deformation graphs can be produced immediately in an electronic format. MSP added another quality assurance method to provide an improved service to our customers and ensure they receive quality products.”
MSP began its first horizontal press testing in January 2014, and Engelbrecht indicates that the company is in the final stages of completing the side load mechanism, in order to ensure that the press is entirely complete and ready for service. “MSP is also currently in the process of field testing the new Shredderbolt, which will be fully tested on the horizontal press too.”
According to Engelbrecht, MSP has invested approximately R3.5 million in the dynamic testing facility, which has taken three years from concept to completion. “A major advantage of the dynamic testing facility is the fact that we can physically test all of our products in ‘real-life’ applications, as opposed to relying solely on computer software simulations.”
The MSP vertical press consists of a top platen that can be adjusted for different sized samples to be tested. A bottom base housing the hydraulic cylinder extends 3.5 m underground and has a moveable middle platen. Hydraulic oil is pressurised and stored inside two large hydraulic accumulators, this allows for enough energy to be stored to produce the 6850-ℓ-per-minute needed to achieve 3-metres-per-second movement of the middle platen. The oil is released into the cylinder via two 100 mm logic valves, which is the largest in Africa.
Engelbrecht adds: “When the oil is released at such high speeds and pressure, it causes the middle platen to jolt up at 3-metres-per-second, which simulates various degrees of seismic activity that may be encountered underground. What’s more, the middle platen of the press moves up from the bottom at 30-mm-per-minute during the static load testing at up to 100 tons of force. A load deformation graph is then plotted for analyses.”
MSP selected Gauteng Metrology Services to design, manufacture and install the in-house hydraulic press. “The company boasts in-depth skills and expertise with regards to this type of equipment, and is also responsible for its calibration and certification,” notes Engelbrecht.
Looking to the future, Engelbrecht believes that the MSP in-house dynamic testing facility will add substantial value to the company’s product and service offering. “This facility enables us to work closely with rock engineers to determine exactly what they require for their specific project. It also places MSP in the unique position of being the only company in the local market that can fully substantiate its product quality in terms of physical testing,” he concludes.
Vereeniging-based MSP is a globally recognised manufacturer of products and solutions for underground mining applications, and is jointly owned by international manufacturing and engineering company DCD Group, and Robor – a world class manufacturer and supplier of welded steel tube and pipe, cold formed steel profiles and associated value added products.