Posted by: admin November 10, 2015

PROJECT DESCRIPTION:

In November 2014, drilling of our southern coalfields vent shaft project reached its target depth of 516m. This is the deepest blind-bored shaft ever constructed by Abergeldie. It is a monumental achievement for the drilling team; even greater considering the shaft’s unusually broad 6.2m diameter and the challenges of very hard rock in the lower strata.

Fabrication of the 170 composite steel/concrete liner units was carried out in a temporary factory facility which Abergeldie set up on-site. Each segment is 3m deep, with a finished internal diameter of 5m. Once all the liners were installed, the annulus between the drilled shaft wall and the liners was filled with grout to give a smooth, hydrostatic finished surface.

Another of the team’s major challenges was working to the treat the drilling process water. The blind boring process uses up to 18 million litres of water, which carries away the drilled spoil as suspended solids. The concentration of suspended solids can be as high as 70%. The solids had to be removed so that the process water could be reused again and again as boring proceeded.

Despite some delays in drilling due to unusually difficult ground conditions, the project was successfully completed June 2015. Abergeldie is proud to deliver this significant project for a very valued client.

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PROJECT DESCRIPTION:

Abergeldie was contracted by Centennial Coal’s Newstan Mine to sink and line a 180m deep, 6m finished diameter shaft. Liners were steel only rather than the traditional steel/concrete composite liners which have been previously used on other shafts.

Complex Challenges:

Due to clay bands in the strata Abergeldie used drill muds to prevent water absorption and maintain the integrity of the shaft walls. The unstable ground meant a large amount of soil needed to be excavated and benched to successfully install the pre-sink foundations. The sites footprint was very small and, as such this constraint has required the some creative thinking and ingenuity in installing the sedimentation ponds. Careful calculations and lateral thinking allowed the installation of 2 sufficient sedimentation ponds to allow for effective settling of the water which to be then used in the reverse circulation process of removing cuttings from within the shaft.

* Photos are courtesy of Centennial Coal

Posted by: admin November 11, 2015

PROJECT DESCRIPTION:

Winner – Category 3 NSW CCF Earth Awards 2013
The Ulan West Ventilation Shaft contract was for design and construction of a 4.5m finished diameter, hydrostatically lined, vertical ventilation shaft to a depth of 46m to serve underground coal mine workings at GlencoreXstrata’s Ulan West Operations.

GlencoreXstrata accepted Abergeldie’s proposal that blind boring be adopted as methodology for sinking the shaft, and that welded steel liner segments be used in lieu of the originally proposed segmented concrete liners. The blind boring rig used for the project is owned and operated by Abergeldie, and is one of the largest of its type in the world.

Abergeldie was required to design the shaft, mobilise all machinery and supporting facilities to site, set up and operate the blind bore drilling rig, carry out bulk earthworks for the construction of on-site sedimentation ponds for recycling of the drill process water and to collect drill spoil from the cutting head, arrange fabrication of the steel liner segments for the shaft, install the steel liner segments and weld them together into continuous hydrostatic surface.

Despite some delays in drilling due to unusually difficult ground conditions, the project was successfully completed June 2015. Abergeldie is proud to deliver this significant project for a very valued client.

  • Design and detailed drawings
  • Site establishment – installation, maintenance and removal of environmental controls, amenities, offices and storage areas
  • Installation of site security fencing
  • FRP concrete construction of the reinforced concrete shaft
  • Collar and pre-sink
  • Excavation, support and lining of the shaft
  • Transport, stockpiling and placement of excavated material
  • Dewatering and sealing of water bearing strata – including
  • Providing suitable storage ponds and filtration system
  • Design, supply and install shaft security decking and
  • Removable cover plate

Practical thinking and careful planning resulted in the shaft being successfully delivered on time and on budget with zero safety/environmental incidents and within the specified window of availability of Abergeldie’s blind boring drill rig.

Scope included:

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PROJECT DESCRIPTION:

Design and construction of two shafts two x 230m deep vertical shafts (shaft 4 @ 5.5m diameter and shaft 5 @ 4m diameter) for Ravensworth Mine. Site works included site establishment, survey and set out, construction of shaft collar, presink and drill slab, site clearing and excavation of ponds, construction of liner preparation area.

Work on shaft No.5 was completed in full and Abergeldie supplied and installed composite liners for the shaft to provide hydrostatic seal with 20 year design life, however, the client’s changing priorities meant that works on shaft No.4 were suspended once the presink and shaft collar construction works had been completed.

INNOVATION AND COMPLEXITY

The two shafts were 500m apart. For efficiency, construction at both sites was served by a single works compound, office, fabrication yard and workshop located mid-way between the two.

The blind bore method allows the shafts to drilled and lined without the need for any personnel to enter the shaft during construction, and with no interruption to normal mine production. During drilling and lining, the shafts are kept full of water. Drilling spoil suspended in the water is pumped to settling ponds, and the water then recycled as further drilling continues. The Abergeldie blind bore drilling rigs used are at least fifty per cent larger than any others of its type in the world.

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PROJECT DESCRIPTION:

Construction of a vent shaft 5.5m finished diameter and 320m deep. The scope of works includes the manufacture and installation of composite steel and concrete liners to provide full hydrostatic seal with 20 year design life.

Site works include establishing site facilities, survey and setout, construction of shaft collar, pre-sink and drill slab, site clearing and excavation of ponds, and construction of liner preparation area.

Complex Challenges:

An additional 40m depth of the shaft will be steel liner only (bringing the shaft to 360m deep) and the diameter will step in as the steel liners will be drilled and installed after the composite liners are grouted in place. A gap is to be left between the composite and steel liners for mine access to the coal seam.

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PROJECT DESCRIPTION:

Blind boring of a 465 meter deep, vertical shaft for ventilation of and access to Austar’s Stage 3 underground workings at their Hunter Valley coal mine. With an on-site fabricated, composite steel and concrete hydrostatic liner, the shaft has a finished diameter of 4.5 meters.

Complex Challenges:

Construction required a high level of accuracy. The challenge was to maintain true verticality throughout the entire depth, to within 250mm of its centerline to eliminate complications when transporting workers and materials through the shaft. There was an allowable tolerance of 0.05 per cent for the entire shaft length. A directional pilot hole was drilled for the drill head to follow.

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PROJECT DESCRIPTION:

Design and construct two x 270 metre deep ventilation shaft, one of 4m and the other of 5m finished diameter. The shafts were blind bored from the surface and lined using remote methods. The shafts were completed prior to the underground tunnels reaching the location of the shaft bottom.

On-site facilities were all purpose built as there was with no existing infrastructure. The scope of works included design and construction of an 11 km access road, an electrical substation, three bridges, site clearing, fencing, establishment of a site compound, water reticulation from Cordeaux Dam, earthworks to create settling ponds for the reverse circulation process, construction of a precast yard for casting and curing of 174 composite steel and concrete liner segments; and foundations for fans, shaft collar and the drill rig.

Complex Challenges:

The site was nominated as highly environmentally sensitive as it lies within the Sydney Catchment Authority (SCA) area, only 500 metres from Cordeaux Dam, which is a major SCA water storage facility. Stringent management controls were necessary to contain the large volumes of water required on site for blind boring process, as no tolerance was permitted for discharge of any run-off from the site was. There were no environmental or safety incidents through the life of the project.

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PROJECT DESCRIPTION:

Due to our success in completing works at North Goonyella Ventilation Shaft No. 4, Abergeldie Mining (formally Ardent Underground) was engaged to bore and line the mine’s Ventilation Shaft No. 2. The scope of works included design and construction of an access road, construction of settling ponds required for the reverse circulation process, establishment of an on-site facility to pre-cast and cure composite steel and concrete shaft lining segments, manufacture and installation of a 5.2m diameter composite reinforced concrete and steel liner from surface to 272m depth; and construct of a concrete shaft collar and presinks.

Complex Challenges:

The Shaft was bored from surface to 84m depth at 6.8m diameter and steel lined through Tertiary strata. Then remainder of the shaft was completed at 6.15m diameter to coal seam level at 272m total depth. Abergeldie owns and operates three blind bore drilling rigs, the largest of which is capable of sinking shafts up to a diameter at least 50% larger than can any other blind boring rig in the world. No other rig in Australia would have been capable of blind boring a shaft of the diameter required for this project.

Posted by: admin November 23, 2015

Project Description:

Design and construct 2.5m finished diameter shaft 260m deep. Upper 108m of strata consists of Tertiary deposits of saturated sand, clay and lignite overlain by fresh basalt with comprehensive strengths of over 300 MPa and weathered basalt near the surface. The Tertiary was drilled using 3.15m diameter cutter head to provide clearance for a 2.7m diameter externally reinforced intermediate steel liner extending into the Permian sandstone at 113m depth. The remainder of the shaft is drilled at 2.65m diameter to the production coal seam level 257m total depth from surface. A heavy wall 2.2m diameter external ring reinforced steel liner was installed from the top of the coal to one metre above surface grade.

Complex Challenges:

The entire construction sequence of drilling and lining the shaft is completed while the hole is filled with drilling fluid. The drilling fluid includes additives intended to stabilise the excavation by inhibiting the clay and shale from swelling and subsequent deterioration while protecting the sand from erosion until the steel liners have been installed and grouted.

Posted by: admin

Project Description:

Design and construct a 4.25m diameter 380m deep shaft with a 3.5m internal diameter shaft lining installed to 357m deep. The ventilation shaft was drilled by blind boring methods which provided a safe and effective process for the ground conditions at Springvale Coal. The steel encased concrete liner is 100 per cent watertight and will be maintenance free for an estimated service life of thirty years.

Complex Challenges:

The upper 63m of strata consists of weak, weathered sandstone. This section was drilled at 4.6m diameter and an intermediated casing installed to stabilise that zone.

All of the excavated rock cuttings were brought to the surface. This was important to mines such as Springvale where a minimum number of development headings would make it difficult to handle and remove cuttings from the mine.