Alliance Contracting Solutions Limited have currently commenced working with the Coal Authority on Commercial works for Durham County Council to carry out remedial works to an existing shaft.
The Shaft requires the existing fill material to be consolidated through the injection of phenolic resin between 11.5m and 3m below ground surface elevation and then capping with a reinforced concrete shaft cap founded on 12No piles.
The drilling for the grouting works is to be undertaken using angled drilling from a suitably designed platform gaining support from outside the collapse zone. A monument over the shaft together with an adjacent retaining wall are to be demolished and removed to tip off site during excavation works.
Micro piles are to be installed following completion of the grouting works to support the new 5.6m x 5.6m square 0.5m thick insitu reinforced concrete shaft cap.
The excavation for the shaft cap is adjacent to a live highway and Alliance Contracting Solutions Limited is responsible for all liaison with the highway authority regarding the excavation works and for arranging any highway closures, diversions and associated signage.
Alliance Contracting Solutions Limited has carried out a CAT scan and Ground Penetration Radar survey prior to hand digging trenches at the location of all drilling and piling works to identify any utilities present ensuring that the works are clear of obstruction.
As final reinstatement Alliance Contraction Solutions Limited will be laying new edgings to the rear of the footway in place of the existing retaining wall and then reconstruction of the adjacent footway together with extensive landscaping all to the satisfaction of the Local Authority.
A safe system of work is being employed when working in the exclusion zone (12.8m diameter) namely a temporary platform supported from outside of the collapse zone and this will remain in place until the cap has been constructed.