Underwater demolition (before) |
Underwater demolition (after) |
Nonex is manufactured to be ‘water resistant’ for application in wet holes.
Tug jetty Final Blast
Underwater cartridges designed for waterproofing to 3 bar pressure are available for harbour dredging, widening and deepening projects, successfully accomplished in combination with professional offshore specialist companies such as Durban’s Subtech, Cape Town’s Prodive Solutions, Namibia’s B4 Engineering, Gansbaai’s Gamco Services, and others.
Nonex is suited to underwater application. The absence of detonating shockwave means that environmental damage is avoided; divers don’t need to retreat more than 20 metres. Harbour projects which are normally sensitive therefore have an additional rock and concrete breaking option.
Nature of Rock
Rock varies in terms of hardness, elasticity, abrasiveness, competence, uniformity, and jointing, all of which impacts upon the way it breaks or resists breaking. Surface rock is frequently weathered and fractured, particularly where prior blasting with conventional explosives has taken place on the site. Fractured rock is more difficult to break than competent rock because it leaks gas. Rock is never too hard to break on tensile. Most hard rock will break at or before 250 Mpa, whilst expanding gas pressure is capable of rising to >1000Mpa. It is not the ‘hardness’ that counts, it is the size of the burden/spacing and depth of the hole drilled, (ie oversize) which resists breaking.
An experienced Nonex initiator ‘reads’ the rock, observes the first initiation, fine tunes burdens, spacing, drill depth and charge weights. He successfully interprets what is happening and adjusts accordingly.