Mining contractor Murray & Roberts (M&R) Cementation has been
awarded a contract by Palabora Mining Company for a 1 200-m deep ventilation
shaft.
The shaft, with a lined diameter of 8.5 m, will reach a final blind sink
depth of 1 190 m before a drop raise takes it to its final depth.
M&R Cementation project executive Braam Blom says the duration of the project is expected
to be just more than three years.
“After mobilisation, site establishment and surface civils have been
completed, we expect to conduct pre-sinking until the end of 2019, with the use
of our special shaft sinking gantry to a shaft depth of 65 m.”
“A surface headgear and winder installation will then be constructed
from January to March 2020. This will facilitate the slow sink to 200 m and the
main sink until February 2022. Canadian shutter and lining methods will be
employed. The team is expected to conduct shaft stripping by mid-April 2022 and
to dis-establish the site by the end of May 2022,” he explains.
Blom adds that there will be no stations or other excavations required,
so this will help keep the team in a sinking cycle and optimise production
levels.
A relatively small labour force of 123 people will allow for steady main
sinking conditions, with some subcontractors conducting surface piling and
civil works for the winder and headgear and other site construction.
Shaft drilling itself will be done with two twin-boom Komatsu shaft
drill rigs, and mucking by a Komatsu excavator with close to a ton of loading
capacity.
“Ground conditions are expected to be a challenge in some areas, as profiled from the cover and core drilling. However, we have various ways of reducing the risk and downtime during these intersections – such as keeping the shaft lining as close as possible to the shaft bottom,” says Blom.http://www.engineeringnews.co.za/article/mr-cementation-awarded-palabora-ventilation-shaft-contract-2019-03-18/rep_id:4136
