SHAFT SINKING
As part of Cementation Americas’ plan to reduce cost and complexity in poor ground at a shallow sinking project in Nevada, a simplified structure that sat directly on the shaft collar was used to move the sinking stage, concrete forms, etc
with the blind sinks going down to a depth of approximately 600 m at diameters of 5.5 m and 7.5 m.
Henley said in late July that the VS8 shaft was progressing well and building momentum.“ VS7 started slightly behind and is still ramping up, including the ongoing establishment of water rings and pumping system,” he added.
As well as the use of a common BESS, the VS7 shaft is using electrically coupled single drum winders for sinking, operating in conjunction with a battery that acts as what Redpath refers to as an“ electrical counterweight”. This provides at least the same energy efficiency as a friction( koepe) winder does via its mechanical advantage, according to Henley.
Outside of project specifics, Henley reported on the in-house development of a bespoke SIL2 wireless shaft communications system for use in hazardous areas such as underground coal mines, with good results having been received following commissioning at a site.
He added:“ For deeper, non-hazardous area applications, Redpath have recently progressed into the proof of concept testing for a safety-rated rope communication network solution in a continued effort to reduce reliance on complex wireless communications systems within our operations. Promising results have been achieved with HD video and safety PLC data successfully transmitted via the hoisting ropes at a depth of 1,300 m and operating at 5 m / s.”
A common offering for the global mining marketplace
Cementation Americas is already feeling the positive impact of a progressive move away from diesel-powered production machines, with the company having acquired two Caterpillar R2900 XE diesel-electric loaders for its operations.
Eric Smith, Managing Director, Cementation Americas, told IM:“ We have seen reduced ventilation demands along with better equipment performance [ for the R2900 XEs ] compared to fully diesel equipment, and no battery handling infrastructure required( a big issue with existing mines that were not designed for battery-electric vehicles( BEVs)).”
Smith said the contractor is excited about continuing down the path of acquiring diesel-electric equipment when needs arise and is open to working with clients considering full BEV fleets for their new mines.
Technology acquisitions such as this will be aided by the company’ s new owners, Differential Capital, which Smith was equally as effusive about.
A consortium of investors led by Differential Capital recently acquired, following a business rescue process, all the former mining assets of Murray & Roberts Ltd. The mining assets include Murray & Roberts Cementation Pty Ltd, which carries on business as a mining contractor in Africa, as well as Cementation USA, Cementation Canada and Terra Nova Technologies Inc. Smith said on this change:“ We are looking forward to having a stronger shareholder that is solely focused on holding and growing companies that are servicing the mining industry and not distracted by holdings that are outside of this sector. Our new shareholders will support us with acquisitions, new technologies as well as integrating with our sister company, Cementation Africa, for a common offering for the global mining marketplace.”
When it comes to shaft sinking specifically, the company’ s raiseboring prowess recently came up in a review of the dual shaft return air raise project at Vale Canada’ s Thompson T3 nickel mine in Manitoba, Canada.
For this project, which involved a major ventilation upgrade to help extend the life of the mine, Cementation Americas completed the longest single pull raisebore project ever in the western hemisphere at 3,529 ft( 1,076 m) long. The company then doubled the feat by completing a second raise nearby, providing twin ventilation shafts for the mine.
To achieve such a milestone, the company leveraged the use of its in-house Strata 950 drill, a unit capable of handling“ a lot of torque”, Smith said.
“ Whether it be for a long-distance raise in good rock that will maintain wall stability during the reaming process, or a large diameter raise, the Strata 950 handles our longest and largest diameter holes for clients,” he said.
The longer holes require good rock conditions that are self-supporting, such that the walls of the raise will remain stable without additional ground support until the reaming is complete and the raise can be accessed to install such support. In many cases the rock cannot be self-supporting, in which case alternative raising methodologies need to be pursued, including raisebore to a smaller( but more inherently stable) reamed diameter and slash the excavation to full size using drill and blast or other techniques, according to Smith.
“ In most cases the geotechnical considerations of the host rock the raise is being excavated in is the limiting factor, not the capabilities of the Strata 950 machines,” he said.
At the other end of the scale, Cementation Americas used its expertise to construct a relatively small( around 500-ft deep) ventilation shaft from an underground mine to the surface in Nevada.
“ Due to some of the poor geological conditions of the host rock, there was a lot of geotechnical risk in using a raisebore machine to even excavate a pilot raise that could be enlarged with other methods,” Smith explained.
This saw the Cementation team come up with a“ very unique” solution to get blasted rock out of the shaft by gravity, where a steel-cased hole was drilled and installed
International Mining | SEPTEMBER 2025