GROUND SUPPORT
DSI said that combining the strengths of Jennmar and DSI organisations would allow DSI“ to offer its customers the most comprehensive portfolio in ground support products and services. Envisaged improvements will significantly enhance DSI’ s customer service level and R & D resourcing, while further improving its cost position. DSI will be in an excellent position to offer its customers an unmatched quality of service and build on its further strengthened global presence in the current subdued economic climate of the mining industry.”
Patrik Nolåker, Group CEO of DSI, commented on the transaction:“ Soft commodity prices and supply / demand imbalances represent important challenges to our customers in mining. Through this acquisition, DSI will combine the strengths of two well-established market players, which will allow it to provide its customers a superior offering, both from an efficiency and a product & service portfolio perspective.”
In a separate agreement, Jennmar agreed to acquire DSI’ s Mining business in the United States, which will be integrated into Jennmar’ s existing US business. The combined business will be controlled 100 % by FCI( Jennmar) and operated under the Jennmar brand. DSI’ s Tunnelling business in the US will remain 100 % owned by DSI.
“ DSI’ s strong presence in Western US hard rock mining will further strengthen Jennmar’ s position in this segment of the market. On the other side, its activities in coal mining will complement our existing strong footprint and close some gaps in our offering”, explained Tony Calandra, Executive Vice President of Jennmar, at the time.
New rock bolt technology
The DSI-PEAK Resin Bolting System is a recent development from DSI Australia that it says ensures more efficient and productive working cycles underground. Furthermore, it is a major step in moving the mining industry away from excessive bolting practices towards high quality, lower total cost solutions. The bolting system is an optimisation of long-term mining industry experience and customer feedback from site and lab testing.
“ The DSI-PEAK System captures the various advantages of both point-anchored and fully encapsulated bolts, while eliminating disadvantages and hidden technical deficits that have crept into current industry practice, hindering efficient mining. The system also makes for easier and optimised ground control through less strata damage during bolting than during the installation of conventional rock bolts. Thanks to the shorter anchor and resin cartridge lengths as well as the reduction in
bolting patterns, tangible cost savings are created for primary support, and the need for secondary support is reduced.”
The rock bolt system is based on the newly developed, high-impact“ AK” steel grade and features a unique bar profile to optimise localised micro-mixing and reduce longitudinal pressures during the mixing sequence. In comparison to similar 30 t rock bolts, the DSI- PEAK Bolt is shorter and uses a larger hole size to reduce back pressure on bolt thrust. The system’ s 2:1 FASLOC ® resin provides effective mixing in up to 30 mm bore holes and reliable top anchoring with reduced bolt lengths.
Greater load bearing capacity at the hole collar and plate, along with improved pretensioning, are achieved through increased nut length. A greater load bearing area into the strata is achieved by a larger surface area plate. The correct tightening sequence and bolt tensioning provide an effective 0.5 m beam. The DSI-PEAK System is available now from DSI Australia.
DSI Underground has also just signed an agreement to manufacture and sell the patented Dynamic OMEGA-BOLT ® with Northern Mining Products( NMP) of Luleå, Sweden.“ In their quest for higher grade ore, underground mines around the world are going deeper and deeper, where rock mass is often highly stressed by the weight of overlaying strata and by tectonic forces. During the process of developing large excavations, dangerous phenomena such as micro-seismicity and rock-bursts may occur, with violent explosion-like ejection of rock fragments. In order to mitigate the risks of such events, dynamic rock support systems have been developed and among them NMP has patented a highly innovative dynamic rock bolt.”
Dynamic OMEGA-BOLT is a mining and tunnelling reinforcement system based on DSI Underground’ s well-known expandable“ OMEGA” friction bolt equipped with an internal additional steel element having a“ C” profile. While the external omega profile is in contact with surrounding rock along its entire length, the internal element is welded only to rockbolt’ s two ends. Being fully“ de-bonded”, the internal“ C” element is able to elongate and absorb a great amount of elastic energy released by the rock mass.
The Dynamic OMEGA-BOLT does not require any bonding material such as resin or cement grout, and offers immediate support for extra safety and high productivity, especially in case of fully mechanised bolt installation.
Anders Dalstål, CEO of NMP comments:“ With its professional technical and sales team, DSI Underground is the perfect partner for NMP. We are confident that DSI will fully utilise the technical and commercial potential available in our patent and will support the continuous
The Dynamic OMEGA-BOLT ® is a mining and tunnelling reinforcement system based on DSI Underground’ s well-known expandable“ OMEGA” friction bolt equipped with an internal additional steel element having a“ C” profile
development of the Dynamic OMEGA-BOLT. DSI’ s global presence will make Dynamic OMEGA-BOLT well known in all mines where micro-seismicity and rock-bursts may cause injuries to miners, from Scandinavia to North and South America, Australia and South Africa.”
Reich comments:“ After the recent acquisition of the One-Step rock-bolt, Dynamic OMEGA- BOLT represents another important addition to our product portfolio of highly specialised bolt technology. Dynamic OMEGA-BOLT offers a unique value proposition and has potential to significantly increasing productivity with several customers. This acquisition and the ongoing joint efforts with our partners at Northern Mining Products confirm DSI Underground’ s continuous interest in technically advanced solutions to make Underground Mining safer and more efficient.”
But new ideas also come from grass roots academic instutions. Nearly four years in the making, an undergraduate project from Professor Ming Cai’ s course at Laurentian University School of Engineering has produced a technology innovation that aims to improve mining safety and rock stabilisation, referred to as the Superbolt.
Cai’ s Superbolt design features a MCB33 modified cone bolt with a resin-mixing blade, a cone, a reinforcing / de-bonding agent( a corrugated steel pipe), a dome nut, and a dome plate. The de-bonding agent of the steel pipe, coupled with its strength and rigidity, allows for further rock reinforcement. While the Superbolt is physically strong, it can also effectively absorb dynamic energy that is released during a rockburst because of the unique design.
“ The bolt has both reinforcing and yielding support capacities, and it can be installed quickly. Thus, it offers potential savings for mining companies to develop mines faster and have effective support with this bolt,” he says. Cai says the development of more effective rock bolts, like Superbolt, can improve mine safety, especially in Sudbury and other regions with deep mines.
48 International Mining | AUGUST 2016