It is generally acknowledged that South Africa’s narrow-reef mining sector is in a precarious state, as its viability is challenged by declining global commodity prices, labour instability, uncertain government policy, overregulation and declining productivity.
Adding to the problem is mine managers' apparent apathy to embracing innovation to ease these burdens. Mining is by and large a price taker and cannot pass on cost increases to the final consumer; therefore, solutions to improve efficiencies are vital to the survival of the industry. This according to blasting solutions provider Master Blaster CEO Mark Davis.
He contends that modern mines’ problems cannot be solved by yesterday’s technology. Davis notes that mining service and equipment suppliers have been compelled to cut prices to the extent that there is no more room left for them to manoeuvre. At the same time skill levels in the mining and explosives services industry are declining rapidly.
“Consequently, meaningful innovation has suffered, whereas for any industry to survive and grow, innovation is vital. Unfortunately, the narrow-reef underground mining industry in South Africa is inclined towards iteration not innovation despite undertakings to investigate new technology,” Davis asserts.
He says that the batch type process of mining in use over the past 100 years is a constant reminder of the paralysis of the situation, which, while the impossibility of fully mechanising underground narrow-reef operations needs to be acknowledged, demands “genuine introspection”, which is “seldom undertaken”. Davis states that the blame is too often directed at the geology, the mining method, uncompromising labour unions and regulators who are “too quick” to apply punitive measures, where positive solutions are needed.
Davis elaborates that the fundamental problem with the batch type operation is the downtime required owing to the dispersal of gasses following a blast to prevent endangerment of mineworkers. Davis notes that re-entry after blasting in a 24-hour cycle can take between 3 to 6 hours.
He comments that the continual decline in underground efficiency is highlighted by the fact that an average gold mine breaks around 60% of what is drilled, while platinum achieves around 70%. “Both only blast around 13 to 14 times per month out of 22 available shifts.”
Davis remarks that underbooking, or carrying out less blasting rounds than is required, remains an “undeniable problem” in South Africa’s narrow-reef mines and has to be solved to rescue the billions of rands it costs the industry yearly.
Fall-of-ground (FoG) incidents continue to plague the industry. He highlights that FoGs are caused mainly by deteriorating ground conditions and the use of the wrong explosives.
Davis says that the gold mining industry has predominantly used pneumatically loaded ammonium nitrate fuel oil (Anfo) explosives for decades, “knowing that these are the worst possible explosives in terms of health, safety management and responsible corporate governance”. He notes that the low unit price of Anfo masks the wider costs of the negative fallout, which far outweigh any supposed immediate price benefit.
The same applies to bulk explosives loaded mechanically into short, small diameter narrow-reef holes. Davis explains that despite being slightly less 'offensive', bulk explosives loaded mechanically are probably worse than pneumatically loaded Anfo in every other respect, however.
Moreover, he points out that the geology in narrow-reef mines dictates that burdens and spacing cannot be significantly increased so the use of bulk explosives as an alternative to Anfo simply increases costs.
Davis states that stemming of bulk explosives in short, small diameter holes is, if compliance with Department of Mineral Resources’ (DMR’s) regulations is adhered to, “almost impossible”, and in the case of mishap, raises the likelihood of costly Section 54 work stoppage notices for noncompliance.
He points out that the density of mechanically loaded bulk explosives is about 20% higher than pneumatically loaded Anfo, therefore, more explosives are loaded in each hole aggravating the hanging wall condition and exacerbating underground safety risk.
“Naturally, the suppliers of bulk explosives are the same companies that have supplied Anfo to the industry for the past 50 years and suffer little consequence to their bottom line with the switch from Anfo to the more dangerous bulk product.
“It must be noted that these are basically the same bulk explosives that have been around for the past 35 years and were never introduced into the narrow-reef mines, while Anfo was the explosive of choice. One can only speculate as to why?”
Moreover, Davis notes that every hole blasted with explosives creates a crushed zone during the detonation process and all the metal in this zone is lost. However, he says that, although the extent of the crushed zone in various rock types is debatable, its existence is not.
Davis comments that currently every 1.2 m hole fully loaded pneumatically with Anfo results in a gold loss of about R120 in the crushed zone. Higher density, more powerful bulk explosives clearly result in a larger crushed zone and more lost gold or platinum. He emphasises that this is not a new phenomenon, rather it is just not talked about by the large explosives companies.
“For example, given the number of holes blasted in diversified miner Sibanye’s gold and platinum mines, the metal lost in the crushed zone amounts to well over R1-billion yearly,” Davis contends.
He highlights that working and living conditions, salaries, bonuses and the threat of job losses are the foremost concerns of labour unions, which, therefore, are unlikely, realistically, to consider adding their voices to calls for the innovation Davis puts forward, especially in a climate where mineworkers’ concerns are informed by the talk of wholescale mechanisation as the only solution to underground narrow-reef mining’s problems, even though “mechanisation is simply not a viable option for most South African mines”.
He adds that the lack of meaningful innovation by mining houses will certainly not improve the lives of workers or gain their trust and, therefore, “confrontation” between mines and labour will persist.
Davis believes that to ensure the survival of the narrow-reef mining industry innovation needs to be at the forefront of every decision made by the mines.
He says that Master Blaster’s 1.4S initiation system can play a significant role in addressing this challenge, as it eliminates the need for traditional explosives. The 1.4S is a propellant based rock breaking system.
“The solution makes it impossible for workers to underbook, as each blast is carried out individually under direct supervision of the whole stoping team. There can also be no more drilling into misfire accidents as the propellant powders and our Maxnel clip system cannot be initiated by impact,” Davis points out.
He notes that the system’s propellant powders produce no shock energy, which ensures improved hanging wall conditions, and therefore a safer working environment.
Even if mines use rock breaking cartridges (RBC) which are detonated in the bottom hole, the RBC in the hanging wall hole will be initiated with an igniter, which will produce no shock wave and hence it cannot damage the hanging wall.
“Our system will greatly assist in ensuring continuous mining occurs, which will lead to a quantum leap in face advance and dramatically increase efficiency allowing uninterrupted, safe, daily support, drilling, breaking, cleaning cycles for at least 24 shifts a month, and significantly more cost-effective mining operations,” Davis concludes.