Quarry Southern Africa September 2018 | Page 34

ENVIRONMENT IN FOCUS The UK is more advanced than South Africa in regard to quarry rehabilitation, with most of its gravel pits having become water recreation areas for sailing and more. and groundwater quality and quantity, which are the major complaints received at public hearings. “We can test some of the allegations: for instance, there is a process whereby we can assess the structural integrity of buildings to determine if they have been affected by a blast event,” says Hex. Design for closure Rehabilitation of a quarry can have quite a different outcome to rehabilitating a mine. After all, a mine has to be located precisely where the mineral is located — and though the same may be true for a quarry, the feasibility of any quarry dictates the prevailing motivation to locate a quarry near to its market. Cluett Consulting has developed a rehabilitation model which looks at reducing operating costs associated with mine rehabilitation while maximising opportunities upon a quarry’s closure. This is aimed at ensuring a quarry closure does not create an economic vacuum within the local community that often developed around the economic activity created by the quarry — especially if it was the only such generator. 32 _ QUARRY SA | SEPTEMBER/OCTOBER 2018 In a presentation he has prepared to initiate a change in mindset among quarry owners long before looking at closure, Cluett Consulting’s Alan Cluett states: “An area we are exploring is whether the infrastructure left behind after quarry closure can be put to new use. This involves viewing current quarries as a ‘temporary land use’ and that quarry owners are the ‘architects’ of the quarry’s next end use.” Cluett defines ‘sustainability’ as being not just the sustainable use of the mine, but sustainability of the surrounding communities. Where quarries differ from many mines, is they are frequently located either within urban areas as they have been located near to their markets that have either grown up around it, or a town has enclosed it over the lifetime of the quarry, which itself has been core to the development of the local area. Such locations become ideal for residential or commercial purposes, like Eagle Canyon, or a mixed-use complex such as Tygerberg Valley. “These quarries commenced in rural areas but became urban over time because of the nature of the activity: mining a high- volume low-value product where transport is the single biggest factor in its viability, and they consequently try to locate themselves as close to their market as they possibly can.” Jukskei Quarry and Canyon Rock Rossway Quarry were originally located far out of town surrounded by nothing but veld, but today, are almost surrounded by industry and housing estates. This occurs because of their initial location, and also the fact that a quarry has a long lifecycle averaging 30–50 years — while some such as AfriSam Ferro have been going for more than a hundred years, and Natal Crushers in Pietermaritzburg for 215 years. This also means quarry managers have to learn the skills of dealing with encroaching neighbours. While the quarry may have been there a long time and even be the entire reason for the community gravitating towards it, the fact may be that one day those neighbours will be part of the mine’s rehabilitation plan. So, quarry managers need to be concerned not to raise too much dust, and limit drilling and blasting within limits. Such un-neighbourly behaviour today could affect the later value of the site and its rehabilitation. Quarry owners therefore need to view the rehabilitation