Sandvik machines successfully in long-term continuous operation
Following approval in 2002, work began in 2008 to convert the Konrad mine in Salzgitter, Lower Saxony, into a repository for up to 303 000 m³ of low- and intermediate-level radioactive waste. The conversion is due to be completed in 2029 so that the repository can be commissioned at the beginning of the 2030s. During the emplacement period, which will last until around 2060, further underground emplacement sections will be excavated in parallel.
The conversion of the former iron ore mine is complex. For example, the two underground shafts have to be qualified and the transport and storage routes at a depth of around 850 m have to be newly excavated and structurally secured. It is also necessary for existing transport routes to be qualified and in some cases widened, while others are decommissioned and backfilled. For the most part, special process technologies are used that combine tunnel construction and underground mining.
During the entire reconstruction work to create a permanent storage facility, however, no material is removed via the shafts but the excavated material is stored underground. Since 2014, the logistically demanding underground material transport has been organized using Sandvik loaders, among others, of which three Toro® LH514 loaders have now been in continuous operation around the clock for over a decade in three-shift operation to clear old routes, open new routes and move material.
Expansion wanted:
Upgrade and expansion of the Sandvik machine fleet
In 2022, after almost a decade of continuous use in three-shift operation, the three Toro® LH514 loaders received a comprehensive engine upgrade including new exhaust gas aftertreatment to achieve optimized exhaust gas values with new engine technology and to meet the stricter workplace limits and emission standards. The loaders were thus upgraded from Tier 3B to Tier 4Final. As a result, the minimum ventilation requirement per machine was reduced to around a third of the original value. This allows the loaders, which are in very good condition despite over 17 000 operating hours, to be used sustainably for many years to come.
Sandvik was also successful at a public tender for the planned expansion of the machine fleet. In 2022, three more Toro® LH515i loaders were delivered, which with a loading capacity of 15 tons have the largest capacity in their class.
In the same year, Sandvik also supplied two DS311DE rock support bolters, each of which was ordered with two interchangeable bolting heads for different bolt lengths (1800 mm and 2400 mm) and bolt types (resin cartridge and mechanical expansion shell bolts). The machines can be used both in electrical grid operation and in diesel operation, which offers BGE significant added value compared to conventional drilling rigs in terms of flexibility and independence from power grid availability. In addition, the rock support bolters are equipped with a radio remote control for use in working areas that are restricted in visibility and a compressed air flushing system that includes equipment for connecting to a dust extraction system. The DD311 drill rig was added to the portfolio to meet the customer’s requirements for extension drilling and to set up to 24-m-long hollow bar bolts.
The new loaders and drilling rigs were successfully put into operation at the beginning of 2023. However, considerable logistical and organizational challenges had to be overcome to ensure the smooth and safe continuous operation of the machines. These ranged from the detailed transportation and assembly planning of the machines underground to extensive personnel training, during which Sandvik proved to be a reliable and flexible partner for BGE.
Adaptation required:
Assembly under extreme conditions
The narrow dimensions of the shafts and cages meant that the machine components had to meet strict dimensional and weight restrictions (maximum 7.5 tons). In particular, the non-dismantlable components, such as buckets and cabins, as well as the transportation of the machine frames on the narrow 5th shaft level, required detailed CAD pre-simulations.
The assembly itself was carried out in a decommissioned section, which only featured basic workshop conditions. A maximum of two machines could be positioned in the narrow space at the same time, which required precise logistical coordination of the components and assemblies. The long distances to and from the entrance and exit limited the effective working time to around 5.5 hours per day, which resulted in a significantly prolonged assembly time of 6 weeks for a loader and 12 weeks for a drilling rig. Stringent personnel requirements, such as mining health checks and police clearance certificates, as well as the dependence on the BGE for material and personnel logistics, further added complexity.
Overall, assembly under these extreme conditions was a demanding task that required a high level of logistical coordination, specialized personnel and strict adherence to safety and working time regulations. “Without the flexibility and adaptability of Sandvik employees and their willingness to work in partnership with the BGE, the project would not have been feasible under these particular conditions,” says Dennis Neumann, Head of Maintenance for the Konrad repository construction project at BGE, looking back on the collaboration.
Flexibility required: BGE staff training
Training BGE employees to operate and maintain the new machines was equally demanding. The originally planned scope of training was significantly extended on the urgent recommendation of Sandvik. The three-shift mining operation required logistical coordination to train all employees.
At the same time, the new technologies used on the machines, such as the computer-aided control and monitoring systems of the loaders or the rotary percussive drilling system of the drill rigs, placed higher demands on the know-how of the operating and maintenance personnel.
Overall, the training courses for the nine operator- and nine maintenance shifts (three for each type of machine) were therefore significantly more extensive and complex than originally planned and took around twice as long (approx. 2 months). This required flexible adaptation of the training measures and intensive cooperation between Sandvik and BGE to ensure safe and smooth operation of the machines.
Reliability guaranteed:
Continuous operation for decades to come
The ten-year collaboration between Sandvik and BGE on the reconstruction of the Konrad mine into a repository for low- and intermediate-level radioactive waste is an outstanding example of successful project implementation under extreme conditions. Sandvik was able to confirm itself as a trusted partner thanks to the high reliability, safety and performance of its machines as well as its flexibility and intensive support in training and logistics for BGE employees.
“With the successful commissioning of the new loaders and rock support drill rigs, BGE is now perfectly equipped to meet the demanding requirements of the Konrad repository project and ensure smooth and timely project execution,” says Eric Lüpfert, Sales Manager for Underground Equipment Sandvik Mining and Rock Solutions.
And one more thing is certain: the successful partnership between Sandvik and BGE shows how even the most challenging projects can be successfully implemented through collaboration and innovation.
