This question text the cognitive and application skills of the candidates. Candidates’ performance is very poor. The question requested the candidates to give the following points:

Non -explosive blasting

1. Hydraulic splitter: Hydraulic splitter is a low-impact way to break apart rock or concrete.  These splitting tools are inserted into pre-drilled holes and exert a splitting force from within the material
2. Expansive chemicals: Non-explosive demolition agents are chemicals that are an alternative to explosives and gas pressure blasting products in demolition, mining, and quarrying.
3.  Thermal fragmentation: Thermal fragmentation, as the name implies, uses high heat to spall high-grade ore. However, it requires high heat energy, which requires additional ventilation as compared to normal conditions to cool the work area.
4. Plasma blasting: Plasma blasting uses a high temperature and pressure plasma to fracture rock in a safe manner. While this method may be environmentally friendly, its usage may significantly slow tunnel development due to the need to haul one or more large energy capacitor banks into and out of the work area repeatedly.
5. Controlled foam injection: Controlled foam injection is another chemical method, whereby foam is the medium for fracturing. Although claimed to be environmentally friendly, it may still pose safety risks such as air blast or flyrock due to its dynamic nature.
6. Radial-axial splitter: A radial-axial splitter (RASP) is an instrument specially designed to fracture a borehole in the rock face but only at the pace of one hole at a time. Supercritical carbon dioxide is used with the equipment designed to provide a high-pressure jet stream to fracture rock, and replaces water in these instruments.
7. Supercritical carbon dioxide: Supercritical carbon dioxide is used with the equipment designed to provide a high-pressure jet stream to fracture rock, and replaces water in these instruments.