RAVENSWORTH UNDERGROUND MINE VENTILATION SHAFTS NO 4 AND 5

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.

Business unit:

Mining

Client:

Xstrata Coal

Current status:

Complete

Start date:

July 2011

Completion period:

July 2012

Contract type:

Lump sum

Value:

$13.5 million