Historical Background
Earlier in the development of the technology, Nonex rock breaking cartridges were conceived as “safety cartridges”, which were endowed with very high resistance per cartridge, capable of being initiated by a specialized shot firer only, and then up 3-4 cartridges at a time. As a result the Nonex range became known as a safe method of breaking boulders, ‘slyping’ underground row by row and excavating rock for swimming pool installation. It’s application was perceived as being limited, relatively expensive and slow.
Modern Developments
Nxco Mining Technologies implemented a number of significant product developments:
Initiation System
Multiple cartridge initiation was made possible by reducing the ohm resistance per cartridge whilst maintaining sufficient resistance to prevent accidental initiation by static electricity, cell phones and the like. The cartridge range thus maintained it’s UN 1,4S rating for being safe, non-volatile and harmless unless initiated when confined in a drill hole by effective stemming. This development meant that contractors could initiate as many cartridges simultaneously as permitted by the capacity of the shot firer, the cartridges connected in series. MCC, in collaboration with AEC Electronics, soon began initiating mass blasts up to 300 shots at a time.
Expanded Range
Originally, the range consisted of 28mm cartridges because popular drilling underground was 32mm. This range started at 20g extending by 20g to 120g. For surface application by popular demand, 34mm cartridges were introduced, which with a wider ID were shorter in length for the same charge, and permitted an extension of the charges to 140, 160 and 180g. The 180gram Nonex cartridges became a focal point of difficult in-situ and very hard, compressed underground rock as well as decomposed fractured material as can be encountered in trenching, slyping and pillar mining.
Nxco also introduced a range of 12mm ‘rock poppers’, drilled 400mm depth electrically, for application in concrete demolition. We rapidly discovered as contractors that the rock popper range from 3-6g was amazingly effective splitting hard rock to size, such as for the crusher, both on surface and underground
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Nxco also introduced a 60mm range with charges from 200g, 300, 400 and 500g for application with a rig drilling 64-76mm holes to a depth of up to 2,0m, or deeper combined with decking. 500g cartridges produce 500 litres of expanding gas when initiated so when initiating 300 cartridges simultaneously, that means 150 000 litres of gas is produced and looks for space to expand to, thus generating a most powerful but controlled ‘mass blast’.
MCC in South Africa as well as mining contractors in Western Australia rapidly realized that such ‘mass blasts’ retained the inherent safety benefits inherent in the Nonex technology design whereby non-detonating initiation, no shock wave, and limited vibration means that mass blasts can be cost effectively and productively enacted in sensitive, built-up areas such as South Africa’s Gautrain shaft sinking, and in fact any rock or concrete breaking application required where conventional high explosives would be risky at best and dangerous at worst. These developments reduced the down side and enhanced the upside which used to categorize Nonex as a safe, but slow, limited and expensive rock breaking option.
Today, Nonex used correctly has its place alongside mechanical breaking and conventional explosives using electronic detonators for application in highly sensitive, built-up areas as well as environmentally sensitive situations such as underwater and on the seabed.
Nonex is being used in the current process of deepening and widening Durban Harbour by specialized offshore demolition contractors. The product has always been waterproof up to a point, but Nxco have now extended the guarantee to 3 bar pressure, which is for depths equivalent to the world’s deepest harbours.
Apart from the gains in technology, methodology has made significant advances too.
We have learned how to sink shafts using Nonex, how to mine pillars, and in conjunction with dimension stone miners, how to cut granite more effectively than with alternative products. The list of applications goes on and on. For your application, please feel free to call us. Maybe we can help.
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