IM contacted Atlas Copco’s Director of Mechanical Rock Excavation, Mikael Ramström and Johnny Lyly, Global Product Manager for Mobile Miners, for further information on the ongoing evolution of the Mobile Miner family of mechanical rock excavation machines, with additional details covered in the IM December 2017 issue. The latest and last of the three model series to be built, the Mobile Miner 40V, that will be delivered to Hecla’s Lucky Friday Ag/Pb/Zn mine, is typically used in small to medium sized tunnels and cut-and-fill mining when you need a tunnel around 4 m x 4 m in size. V indicates that the cutter head is placed vertically as opposed to the H for horizontal on the 22 H. The capacity of Mobile Miner 40V is 10-15 m/day depending on rock type.
Atlas Copco confirmed that at Lucky Friday the main use of the machine will be mining of the orebody, but its second use will be for development. At Lucky Friday, for example, a major part of the current works is on developing the 6500 level to connect the #4 Shaft to the orebody. Hecla’s decision to opt for the 40V Atlas Copco says “was based on our successful results from Mobile Miner 22H testing in Twickenham and the modelling works done in our joint R&D project as well as laboratory cutting tests on rock samples from Lucky Friday mine.”
As stated, this will be the first Mobile Miner 40V machine to have been built, adding to the Mobile Miner 22H and Mobile Miner 55V machines that already exist. There is now one of each machine in existence making up a comprehensive product portfolio from low/small (22H) over medium (40V) to large (55V) size tunnels. The 22H is typically used in low seam or low profile mining when you need a tunnel as low as 2.2 m and is capable of 10-12 m/day advance depending on rock type. The Mobile Miner 22H will go into “normal operation” at Anglo Platinum’s Twickenham mine starting in early January 2018, following very successful tests that showed there it could achieve over 10 m a day in 140-150 MPa rock hardness. Referred to by Anglo as the Rapid Mine Development System (RMDS), the mining group states: “it excavates a rectangular-shaped tunnel, important for roof stability purposes in platinum mines, for example, as well as providing the flat floor needed by mine vehicles. As well as removing people from areas of most danger underground, the RMDS causes less damage to the overhead walls, thereby reducing the risk of collapse and enables greater ore excavation time as there is no time lost for explosive blasting.”
Finally, news on the Mobile Miner 55V that was originally built for Rio Tinto. This machine was sold by Rio Tinto to the Swedish contractor Bergteamet AB who announced the buy in August 2017 and are now considering projects to put it to use. The 55V is designed for mechanical excavation and has been developed for deep mine infrastructure. It can continuously make reinforced tunnels with a size of 5.5 m x 5.5 m, down to a radius of 65 m and with a flat floor. Of course Bergteamet is based in Boliden, Sweden, so the major underground mines in that region may make good candidates for users, such as Renström, Kristineberg and Kankberg. Bergteamet refers to the machine as a Tunnel Boring System (TBS).
In late 2015 Master Drilling International Ltd acquired 40% of Bergteamet’s raiseboring division and together with Bergteamet AB they formed Bergteamet Raiseboring Europe AB. Master Drilling said at the time it will use the purchase to leapfrog into European and Middle Eastern jurisdictions in its pursuit of geographical diversity. With the purchase, came entry into the Scandinavian markets that were close to inaccessible to companies outside the region. Master Drilling paid €5m for the 40% stake, and has a three-year period in which to buy the balance.
The Mobile Miner product family will belong to Epiroc in the future. It is currently part of the business area Mining and Rock Excavation Technique, which will become part of the new Epiroc. The Mobile Miner product family will follow the same branding policy as all other Epiroc products. An interview detailing the latest news on Epiroc will also feature in the IM December 2017 issue.