FIRST STAGE of the major cleanup of a former colliery at Dinnington, near Rotherham, is expected to start next month following extensive pre-tender works.
AIG Consultants, working for regional development agency Yorkshire Forward, supervised site investigations and bioremediation trials at the end of last year to redevelop the site for a mixed light industrial and business use.
The former colliery is one of 56 sites acquired by English Partnerships in December 1996 from British Coal's non-operational property portfolio. Nearly a third of the 85ha site, which was also the former home of a coke works and brick works, is covered by a spoil tip and there are three mine shafts and two backfilled clay pits. While Yorkshire Forward owns the site, reclamation is being paid for by English Partnerships.
Site investigations revealed that about 100,000m 3of soil and fill was heavily contaminated with tarry waste, principally PAHs, near the former coke works. A significant obstacle to assessing the degree and extent of coal tar contamination was that about 70% of the contaminated soil/fill is overlain by up to 11m of 'clean' colliery spoil (the former coke works tip). Also, the tip includes two former tailing lagoons that contain substantial thicknesses of lagoon sediment (a very soft dark grey sandy clay).
The first phase of work, due to go out to tender in July, is worth £1M and involves relocating some 400,000m 3of the colliery spoil, including 70,000m 3of tailing lagoon sediment, from the coke works tip.
About 90,000m 3of this material will be used to infill a railway cutting and the remainder will be placed on the main tip. This phase will leave the coal tar contaminated soil covered with an appropriate thickness of 'clean' overburden.
The second phase will include treatment, most probably using bioremediation, or removal of the coal tar contaminated soil and fill, ground improvement and some landscaping.
The third and final phase will include improvements to existing site infrastructure, highways, drainage, services and further landscaping.