Miscellaneous Projects

North Yorkshire holds one of the largest, high grade polyhalite reserves worldwide. It is located within the North York Moors National Park, ca. 1800m below surface. Once processed, this mineral functions as an organic fertilizer to boost harvest. Sirius Minerals plc are currently developing the infrastructure to mine the polyhalite. This operation requires deep shafts to access the mineral body but also demands an extensive mass transport system (MTS) to keep the impact on the National Park to a minimum. Therefore, at ca. 350m below surface, a series of SCL tunnels link the deep shafts to a conveyor belt system, which again connects the mining operation via a 37km TBM tunnel to its material handling facility.

Luck Stone Corporation (LSC) is the nation's largest family owned and operated producer of crushed stone, sand and gravel. At their plant in Leesburg, Virginia, Luck Stone Corporation acquired a new quarry, which is located to the West of Goose Creek river. An inter-quarry tunnel was constructed to link the existing South-Eastern pit with the new West pit. The tunnel's cross section is approximately 45 feet in diameter, and the tunnel's length is approximately 1275 feet. The tunnel crosses the Goose Creek river approximately 50 feet beneath. The excavation method was drill and blast in hard rock (diabase).

Luck Stone Corporation (LSC) planned to open a new quarry on the Western side of Goose Creek river, a component of the Virginia Scenic Rivers System. A tunnel was envisioned to connect the new Western quarry with the existing South-Eastern one below the river. The rock cover between the tunnel and the river was approximately 50 feet. The tunnel is 1275 feet long with a diameter of 45 feet. It is designed to accommodate large scale mining trucks as well as a conveyor belt for material transport which is scheduled to be installed in the future.

Inspected tunnel connects two quarries at the Luck Stone Corporation Fairfax plant. The tunnel crosses beneath the Lee Highway (US Route 29), in a North-South direction. Built ca. 1975, the tunnel is partially unlined and in rock; approx. 190 feet long and approx. 22 feet wide and 22 feet high. As the Northern quarry side is already exhausted, the tunnel is rarely used with just one or two transits per day.
Dr. Sauer & Partners performed an in-depth inspection of a connector tunnel; assessed the tunnel condition and provided remedial measures.

Los Bronces copper mine, an open-pit operation at an altitude of 3500m ASL in the Chilean Andes, planned to utilise a tunnel for further deposit exploration and development. The project consisted of an 8.2km tunnel link between Los Bronces and Confluencia, connecting two processing plants. By applying drill and blast methods, a chamber was prepared to launch a 4.5m diameter tunnel boring machine which took over further excavation. A difficult geological and hydrological setting, extreme weather conditions as well as the high altitude and the rough terrain, provided a challenging environment.

Shallow underground parking cavern for some 350 cars: constructed in soft ground using NATM excavation 180 m long with a 240m² approx. Cross section (18.9 m wide by 16.4 m high)

British Gypsum's operation at Leicestershire, a plaster production plant, improved infrastructure by establishing 2 new tunnels on site. Ground treatment for the control of water ingress during construction, drift excavation, final lining and a water ingress guarantee had to be taken into consideration. By applying NATM, the tunnel was excavated by roadheader and supported with lattice girders followed by shotcrete. The construction met the final water ingress guarantee by installing a PVC waterproofing membrane between the primary shotcrete lining and the final unreinforced in-situ concrete lining which is of a watertight quality in the invert.