Quarry Southern Africa May 2018 - Page 10

NEWS Poor blasting practices erode mines’ financial bottom lines and are bad for the environment, according to BME technical director, Tony Rorke. Highlighting that many greenhouse gases are generated in the explosives chain, Rorke says that nitrous oxide (N 2 O) is particularly dangerous – at almost 300 times more harmful to the climate system than carbon dioxide. “Ironically, there is little public awareness of N 2 O, which is why it is sometimes referred to as the ‘forgotten’ greenhouse gas,” says Rorke. “However, containing N 2 O emissions can also present an opportunity to mines and other explosives users to significantly improve their carbon footprint,” adds Rorke. Rorke emphasises that there are other downstream activities on a mine that also contribute to the operation’s carbon footprint – and which can also be improved to result in less Blast better for greener results Blasting rock releases greenhouse gases. CO 2 emissions. Research shows that for every cubic metre of rock mined, about 4kg of CO 2 is produced by the explosives, 5kg of CO 2 by the process of loading and hauling and 27kg of CO 2 by crushing and milling – a total of 36kg. An important negative result of a bad blast is difficult digging conditions – loaders will struggle to dig where the required fragmentation has not been achieved, which means the machines will burn more diesel and emit more CO 2 . Coarser fragmentation also leads to less efficient functioning of the crushers and the mill, which will in turn consume more electricity – also a major greenhouse gas contributor. “By blasting badly, a mine will also effectively be losing ore; so, despite creating all these extra greenhouse gases, there is even less ore to show for it,” says Rorke. “The result is that more mining is necessary to reach targeted production levels.” Africa’s GDP. After reaching an eight-quarter high of 127 at the end of 2016, the ACI declined for two successive quarters before recovering in the third quarter. It increased again in the fourth quarter of 2017 by 1.9% to reach a level of 125.4 (see graph 1). The construction sector at large continues to outperform the economy as a whole by a considerable margin, with the ACI having expanded by 25.4% since the third quarter of 2010 (the base period). This is substantially higher than the rate of growth of 15.8% for the economy over this period (in real terms). Andries van Heerden, Afrimat CEO, says that the results of the ACI fourth quarter numbers are encouraging and he is hopeful that the positive trend will flow into the first quarter of 2018. “We witnessed a reduction in sales volumes during the last quarter of 2017, with the slow-down exacerbated in November and December in construction material products. This was felt more strongly in KwaZulu-Natal and southern Gauteng, where our Glen Douglas and Clinker operation experienced reduced volumes. We nevertheless are optimistic about the change in leadership of the country – there is no doubt that the political uncertainly of the last few months of 2017 worsened the situation,” says Van Heerden. He adds that it is heartening that President Ramaphosa is directly addressing issues the people of South Africa face, that incorporates public private partnerships as well as addressing failings within certain state-owned enterprises, where various bottlenecks make service delivery a problem. ACI gains steam Afrimat recently released the findings of the Afrimat Construction Index (ACI) for the fourth quarter of 2017. For the three months between October and December 2017, the trend broadly followed the upward movement of South 8 _ QUARRY SA | MAY/JUNE 2018