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The new building blocks of block caving

Editorial
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As the level of higher grade, easier to mine ores declines, many underground mining operations are looking at new ways of accessing their ore in the quickest, safest, and most cost effective way possible.

Block Caving is being looked to as one method of bulk mining to access these ores, as it is recognised as one of the most economic underground mass mining methods to extract deep, low grade, massive orebodies that have regular footprints and large vertical extents. 

Speaking to Rio Tinto's Australian general manager for geotechnical engineering and cave management, Andre van As, he told Australian Mining that as Rio Tinto develops its block caving expertise in Australia it is looking to unique technologies to do it in more efficient ways. 

Rio Tinto has been one of the major developers of the block caving methods, implementing it at its former Northparkes mine and the Argyle Diamond mine, with van As stating that "block caving is a very attractive mass mining method". 

The University of New South Wales has looked at developing its own skills in the area and even created a professorial chair in geotechnical engineering to support it, with mining expert Fidelis Suorineni installed in the role mid-last year. 

"This is an exciting [development] that will enable us to develop a world-leading research, teaching and training effort in the growing field of underground mining and block caving," the dean of engineering at UNSW, Graham Davies, stated at the time. 

Head of UNSW School of Mining, Bruce Hebblewhite, explained that "this partnership recognises the importance of geotechnical engineering as a core element for successful and safe underground mining. 

"[Block caving] is the lowest cost underground mining method available and is growing rapidly around the world and there is a significant shortage of people with skills in these areas," Hebblewhite added. 

Some mining machinery manufacturers are also taking advantage of the growing interest in the method, with Caterpillar releasing a new block caving ore handling system late last year. 

The automated system increased the already safer mass mining method by not only improving the way in which the ore is moved, but removing the miner from the face. 

Whilst block caving methods have been around since the 19th century, the technique has been coming along in leaps and bounds, particularly in South America, with van As stating that "the Chileans have been doing it for much longer [than we have in] Australia, most of Codelco's copper mines are block caving operations, and [one of the world's largest mines] Freeport Grasberg in Indonesia is also doing it". 

However despite its applications, not every mine is applicable, van As said, with the uptake depending entirely on whether the orebody is amenable to the operation. 

"We've got a lot of catching up to do in terms of skills and methods in Australia, but we do have a strong competency in research and technology in Australia,  

Rio Tinto has partnered with CRCMining, Newcrest, and Elexon Electronics to develop cave flow tracking systems for use in block caving operations. 

CRCMining's cave tracking technology uses 3D positioning systems to enable real-time monitoring of sensors in the block cave, which move with the ore, to optimise flow of caved materials and minimise ore dilution. 

Whilst there has been similar technology developed before, none have been trialled in actual mine environments before, making this Australian technology a real world first. 

"The Cave Tracker system will enable real time mapping of cave material movement, which can be used to minimise dilution and maximise recovery from caves," CRCMining's hard rock and surface mining program leader Dihon Tadic said. 

"Monitoring the material flow in block caves has not been possible previously, leading to poor control of block cave operations and sub-optimal outcomes. 

"The technology will assist in development of improved caving models, which will enable miners to design better cave layouts, ultimately improving mine safety and productivity," he said. 

Rio Tinto's general manager of geotechnical engineering and cave management for copper, Andre van As, explained the miner's support and backing of CRCMining and its partners, stating "we now have a way of remotely and wirelessly tracking rock mass movements in real-time, and preserve the integrity of the resources". 

"It has application in every method. 

"Previously the industry used dumb markers as a way of monitoring ore flow, such as marked tyres or pieces of steel, but we can monitor as it flows in real time". 

Regarding the technology and this latest block caving partnership, van As said "the real value is in preserving the security and integrity of the resource". 

"By monitoring the flow of material in real-time we can potentially minimise the dilution in recovering ore from the block cave, thereby improving performance. 

"The technology will also significantly improve safety, and enable better management of the mine." 

CRCMining initially developed the Cave Tracker concept, after which it invited Newcrest Mining and Elexon Electronics to develop it into a commercial system, with Rio Tinto now joining the venture. 

Testing as a first generation commercial product is slated for mid 2014. 


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