Tag Archives: Herrenknecht

Anglo American ends DMC Mining shaft sinking contract at Woodsmith project

Anglo American has confirmed its Crop Nutrients business has ended the contract of its shaft sinking contractor, DMC Mining Services UK Ltd, at the Woodsmith polyhalite project in the UK.

Anglo, which only took ownership of the asset earlier this year, said DMC staff were expected to transfer to Anglo American under the Transfer of Undertakings (Protection of Employment) Regulations, and construction progress was due to continue.

DMC was awarded the design and build contract for the construction of the deep shafts at the Woodsmith project back in February 2018 when the project was owned by Sirius Minerals.

This contract would have seen it engineer and construct four shafts at the project in North Yorkshire. Those shafts include a production and service shaft, each around 1,500 m deep, and two smaller shafts associated with the materials transport system, each approximately 350 m deep. It was to sink the deep shafts using Herrenknecht’s Shaft Boring Roadheader technology.

Herrenknecht developed the SBR for the mechanised sinking of blind shafts in soft to medium-hard rock. Based on the technology of the Herrenknecht Vertical Shaft Sinking Machine, the SBR offers improved safety performance compared with conventional shaft sinking methods while also achieving higher advance rates, according to the company.

DMC, itself, had become familiar with the technology after helping successfully sink two blind shafts to depths of -975 and -1,005 m, respectively, at the BHP-owned Jansen potash project in Saskatchewan, Canada.

Sinking activities with the SBRs at Woodsmith, meanwhile, were expected to start next year, with the machines having already arrived on site.

A spokesman for the Woodsmith project said of the DMC contract cancellation: “This new structure provides us with simpler internal processes and allows us to better manage the important transition between the sinking phase and ramp-up to steady state operations.

“It also gives us greater control over processes like local recruitment and training.”

DMC Mining invests in new Sandvik, Herrenknecht equipment for Chile projects

DMC Mining Services says it is ramping up activity in Chile, after being awarded five new contracts at the end of 2019.

One of North America’s premier underground contractors, DMC recently secured work at KGHM’s Franke and Sierra Gorda mines, in the Antofagasta region, in addition to a boxhole boring assignment at Codelco’s El Teniente mine, near Rancagua.

To ensure maximum reliability and performance for its clients, the company has invested in new equipment, it said.

For its drilling project at the open-pit Franke mine, two truck mounted Sandvik DE712 diamond drills have been delivered to site. Two additional units, Sandvik DE881 multi-purpose drills, will follow in order to increase drilling capability for this project and an additional project at Sierra Gorda, a 110,000 t/d of ore open-pit operation, it said.

For the boxhole boring project at Codelco’s El Teniente mine, the biggest underground copper mine in the world, DMC has taken delivery of a Herrenknecht BBM1500 boxhole boring machine. Two additional BBR1500 units are on order, which include back-reaming capability to create larger diameter raises, it said.

DMC said: “We are proud of the progress our Chilean team has accomplished over several short months, and that our clients can always rely on DMC’s dedication, expertise and professionalism on any project, no matter where in the world we work.”

As its Chile team ramps up on these new projects, DMC is establishing a turnkey, comprehensive operation ready to serve not only new Chile clients, but all of the South American mining industry – with raiseboring, shaft sinking, underground mining and engineering capabilities – it said.

Herrenknecht heralds ‘game changer for shaft sinking in soft and medium-hard rock’

Having successfully excavated two 8-11 m diameter blind shafts using Shaft Boring Roadheaders (SBRs) at the BHP-owned Jansen potash project, Herrenknecht is leveraging all the lessons it learnt in Saskatchewan, Canada, to ensure this technology proves to be a “game changer” for the sinking of shafts in soft and medium-hard rock.

Mining contractor DMC Mining Services used two SBRs to excavate the blind shafts at Jansen, with the successful project completion acting as proof of the feasibility and advantages of the Herrenknecht SBR concept for the mining industry, according to the Germany-based company.

In August 2018, the mining industry milestone was achieved with the successful completion of two blind shafts to depths of -975 and -1,005 m, respectively, at the Jansen potash project. For the first time, shafts in the mining business were sunk using only mechanical excavation for this reference project.

Two Herrenknecht SBRs excavated the ground by a partial-face cutting method, using a cutting drum mounted on a telescopic boom. The excavated rock was then conveyed from the bench by an innovative pneumatic mucking system (PNM) and transferred into muck buckets to be hoisted to surface, the company said.

An innovative laser navigation system designed by the Herrenknecht subsidiary, VMT Group, using target units mounted on the SBR and lasers connected to the shaft wall, was used to keep the machines on track.

Herrenknecht, with its experience as a technology leader in mechanised tunnelling, developed the SBR for the mechanised sinking of blind shafts in soft to medium-hard rock. Based on the proven technology of the Herrenknecht Vertical Shaft Sinking Machine (VSM), the SBR offers improved safety performance compared with conventional shaft sinking methods while also achieving higher advance rates, according to the company.

The geological conditions at Jansen, however, were anything but easy. At a depth of around 450 m, the SBR encountered a layer of extremely hard competent rock causing excessive pick wear and low rates of advance. To overcome this and some further hardness challenges, the cutting drum was upgraded to a hard-rock cutting drum and torque output was doubled.

Because an existing high-pressure underground waterway, known as the Blairmore aquifer, posed a risk for water ingress into the shaft, ground freezing was executed temporarily in 2011 by BHP to a depth of approximately 650 m.

A major success in this difficult geology was the use of a mechanical ring erector, which allowed the installation of steel tubbing segments with minimal risk to personnel and a high degree of accuracy, according to Herrenknecht. The steel liner rings were installed through the Blairmore aquifer to assist in the development of a composite steel and concrete watertight liner in both shafts.

Since the project-specific design changes at Jansen required modifications to the SBRs, Herrenknecht, together with contractor DMC Mining Services, refined the SBR technology over the long term. The result is the second generation of Herrenknecht SBR technology.

As an example, the second generation SBR is equipped with an additional stabilisation level that allows the fixation of the SBR centre pipe on both ends. This ensures a stable transfer of the reaction forces from the cutting process to the shaft wall without movement of the machine – even with fluctuating excavation diameter of 8-11 m, as encountered at the Jansen potash project.

In addition to an improved filter system, a new design of the PNM system was installed in the second-generation machine, which results in a higher degree of separation in the suction tank itself, allowing wet material and even water to be handled.

Martin-Devid Herrenknecht, General Manager Mining at Herrenknecht, said: “The technical development of the second SBR generation is based on the lessons learnt from the Jansen project.” Two SBRs of this generation are currently in operation in Belarus and achieving good performance as a result of the improvements made, Herrenknecht said. “This pioneering approach is certainly a game changer for shaft sinking in soft and medium-hard rock, impacting the whole mining industry,” he said.

After the successful excavation at Jansen, another task was to be managed: the disassembly of the huge machines in the deep shafts. To remove the SBR from the shaft bottom, it was necessary to reduce the weight of the machine from 390 t to 340 t. This was achieved by stripping all components off the SBR that were in the excavation chamber. Both SBRs were safely extracted from the two shafts at the Jansen potash project in May 2019.

The Jansen potash project, located approximately 140 km east of Saskatoon, Saskatchewan, is a BHP-owned future potential potash mine with an expected initial mining output of around 3-4.5 Mt/y with valuable expansion options.

Anglo American eyes polyhalite potential with Sirius Minerals bid

Anglo American has gone public with a bid to buy Sirius Minerals and its North Yorkshire polyhalite project in the UK.

The all-cash bid, which values Sirius at £386 million ($507 million), comes shortly after Sirius announced a strategic review for the project that included a broader process to seek a major strategic partner for the asset.

Anglo says it identified the project as being of potential interest some time ago, given the quality of the underlying asset in terms of scale, resource life, operating cost profile and the nature and quality of its product.

The North Yorkshire polyhalite project, which is spilit into two stages, will see product extracted via two mine shafts and transported to Teesside, in the northeast of England, on a conveyer belt system in an underground tunnel. It will then be granulated at a materials handling facility (MHF), with the majority being exported to overseas markets.

Infrastructure development on the project includes sinking the shafts at the Woodsmith mine to access the polyhalite deposit (using Herrenknecht’s Shaft Boring Roadheader); developing a 37 km-long underground mineral transport system using tunnel boring machines; constructing a MHF in Teesside for granulating or chipping the mined material into the final product; and harbour facilities comprising an approximately 3.5 km-long overland conveyor, a ship berth and a ship loader located adjacent to the harbour on the River Tees.

In its announcement this morning, Anglo said: “The project has the potential to fit well with Anglo American’s established strategy of focusing on world-class assets, particularly in the context of Anglo American’s portfolio trajectory towards later cycle products that support a fast-growing global population and a cleaner, greener, more sustainable world.”

Anglo is not new to the fertiliser market having, until 2016, a phosphates business in Brazil. It sold the mine, beneficiation plant, two chemical complexes and two further mineral deposits that made up this business that year to China Molybdenum in a $1.5 billion deal that also included its niobium assets.

Sirius announced its strategic review back in September 2019 after it had to terminate a $2.5 billion revolving credit facility stage 2 financing for the project (to get it to 20 Mt/y capacity) due to a worsening of market conditions for a required bond raising.

This led to the company slowing development across the project in order to preserve funding to allow more time to “develop alternatives and preserve the significant amount of inherent value in this world-class project”, Chris Fraser, Managing Director and CEO, said at the time.

This saw the company lay out a pathway that would still see first polyhalite production in the June quarter of 2022, but could see the ramp-up to stage one 10 Mt/y polyhalite capacity reached in the September quarters of 2025 or 2026, depending on if there was a 12 or 24 month deferral of the planned development scope.

Anglo said, during the first two years after an offer is successfully completed, development work on the project is expected to be broadly in line with Sirius’ revised development plan “although Anglo American intends to update the development timeline, optimise mine design and ensure appropriate integration with its own operating standards and practices”.

It added: “Anglo believes that the project has the potential to become a world-class, low-cost and long-life asset. Sirius has progressed the development of the project to an advanced stage, with construction now under way for over two years.

“Sirius has indicated that this is currently the world’s largest known high-grade polyhalite deposit with a JORC reserve of 290 Mt, with a grade of 88.8%, and a resource of 2,690 Mt. The resource indicated by Sirius has the scale, thickness and quality to be mined efficiently using bulk mining methods through a relatively simple, low-energy, non-chemical production process.”

In addition, Sirius has indicated the project could operate at an EBITDA margin potentially well in excess of 50%, according to Anglo, leaving the project well positioned for strong through-the-cycle profitability with a long anticipated asset life.

“At this stage, the project requires a significant amount of further financing to develop and commission the operation that has proven challenging for Sirius to procure on an economic basis,” the diversified miner said. “Anglo American, as one of the world’s leading mining companies, has the resources and capabilities to help build on the achievements of the Sirius team. Anglo American remains committed to its disciplined capital allocation framework.”

Anglo explained that there is potential long-term benefits in applying its technical expertise in both the development and operational phases, as well as utilising its recognised Operating Model to drive safety and productivity to “world-leading standards”.

“Integration into Anglo American’s global marketing network would provide full mine-to-market capabilities and build on Anglo American’s institutional experience in the world’s major fertiliser markets,” it added.

Sirius’ polyhalite product, POLY4, is a multi-nutrient fertiliser certified for organic use and has the potential to generate demand at a competitive cost that supports a strong margin, according to Anglo.

“POLY4 is an attractive low-chloride alternative to traditional potassium-bearing mineral products on a cost-effective basis. It includes four of the six key nutrients that plants need to grow – potassium, sulphur, magnesium and calcium,” it said. “The use of fertilisers is one of the most effective ways to improve agricultural yields and therefore help to address the anticipated future imbalance between food, feed and biofuel demand and supply caused by a fast-growing global population and limited additional land availability for agricultural use.”

Herrenknecht brings boxhole backreaming to shaft sinking market

Herrenknecht expects to install one of its new boxhole backreaming machines in a mine in Asia later this year, one of the company’s Mining Project Managers, Alexander Frey, told attendees at an SME technical presentation, in Denver, Colorado, last week.

Looking to produce a system able to develop ore passes with simultaneous drilling and lining, the company has adapted boxhole boring machines it has been working on for the past nine years – which use an adapted form of the pipe jacking method – and come up with the boxhole backreaming machine.

This new machine can stabilise the shaft with thrust pipes and a steel liner, which avoids collapses of the shaft or a rework, while reducing the amount of activities in the upper level during mine development.

Herrenknecht has already built one machine and tested it at a mine in the Black Forest of Germany, Frey said. This testing saw the company sink an ore pass with a 2.8 m diameter and 22 m length at an angle of 19°. During this test work in 150 MPa Gneiss rock, Herrenknecht achieved reaming rates of up to 1.3 m/h, Frey said. According to Frey, the machine, which is equipped with a cutterhead like those employed on raiseborers, can cut really hard rock.

He added that the machines would likely be used for safely and efficiently sinking ore passes with a maximum 70 m shaft length and 3 m diameter, but it could also find other industry applications.

Rio Tinto starts up TBM at Kemano Second Tunnel project in Canada

Rio Tinto, together with the Cheslatta Carrier and Haisla First Nations, has celebrated the launch of the tl’ughus tunnel boring machine, a key milestone towards completing the Kemano Second Tunnel project for the BC Works aluminium smelter in Kitimat, British Columbia.

The 1,300 t machine was named by the Cheslatta Carrier nation after a giant snake that, according to legend, once bored through the mountains and landscape around the nearby Nachako Reservoir.

It will dig 7.6 km of tunnel through a mountain as part of a C$600 million ($458 million) project to enhance the long-term security of a clean power supply for the BC Works smelter.

Rio Tinto Aluminium Managing Director Altantic Operations, Gervais Jacques said: “Launching the tl’ughus in partnership with the Cheslatta Carrier and Haisla First Nations is an important milestone for our world-class aluminium operations in British Columbia. Our smelter in Kitimat produces some of the world’s lowest carbon aluminium and this project will enhance the long-term security of its supply of clean, renewable hydropower.”

Construction of the Kemano Second Tunnel project is expected to be complete in 2020. It will supply the Kemano powerhouse with water from the Nachako Reservoir, creating a back up to the original tunnel built over 60 years ago.

Frontier Kemper Aecon has been selected as the main contractor for the project, with Hatch being the EPCM. Herrenknecht has supplied the TBM.

The project will see some 250,000 m³ of tunnel rock excavated by the tl’ughus, while 8.4 km of an existing portion of the second tunnel (excavated in the 1990s) will be refurbished.

Phase 1 of the project was completed in 2013 to coincide with the Kitimat Modernisation project and involved construction of interconnections to the existing portion of the second tunnel.

The Cheslatta Nation selected the name for the tunnel boring machine – tl’ughus – as it shares many parallels with the Kemano second tunnel project, according to Rio.

Kitimat produced 433,000 t of aluminium last year, up from 408,000 t in 2016 and 110,000 t in 2015.