4/29/2023 0 Comments Quarry shooting blocks out technicThe selected techniques were applied at the underground working face of Khewra Salt Mines (Punjab, Pakistan) to extract representative blocks in accordance with a predefined field experimental program. This research work is focused on the comparison of three common and simple dimension stone quarrying techniques including wedges and feathers, expansive cement, and controlled blasting methods for the extraction of rock salt block. 3.24kg of explosive for (6 by 6 by 6) m bench design.Ī salt block is a regular prism of rock salt containing least undesirable cracks which is mainly used for carving artifacts especially salt lamps, tiles and other products. Of the four patterns considered, pattern 2 gives highest recovery (55%) with breaking factor of 15g/m3 ( i.e. In the case 2, dynacord is used for basal cutting. 5kg of Gun powder for (6 by 6 by 6) m bench design). Of the seven patterns considered, pattern3 gives highest recovery (70%) with breaking factor of 23.15g/m3 (i.e. In case 1, gun powder is used for basal cutting. The aim of this research work is to establish a standard breaking factor for bench blasting in dimension quarries that will improve recovery.Two cases were considered. In this research work, breaking factor is used in place of powder factor since breaking is required not powder. In aggregate quarry, series of work have been done on powder factor that gives economical blasting. ![]() It is noticed that majority of the damage in the natural blocks are always from poor extraction method. This shows that prenotched blast hole technique is beneficial to the marble stone mining.ĭimension stone quarry is believed to be type of mining operation that always result to low recovery since what is expected from the extracting operation is a cubical block with no fracture. By use of prenotched blast hole technique the extraction cost can be reduced up to half or one third. On comparison it is clear that cracks in desired direction up to almost five times greater distance can be achieved by using prenotched blast hole technique as compared to D-cord splitting technique. Field study showed that in D-cord splitting method, spacing between holes ranges from 0.08m to 0.0.30 whereas result of experimental trial using notched hole technique showed that hole spacing can be extended from 0.33m to 0.72m. In this paper existing practices are analysed and some new practices introduced to reduce the cost of extraction and also to improve recovery of blockable marble by controlling fracture growth in desired direction. For this purpose a field study was carried out in white marble belt of Rajsamand district, and pink marble belt of Udaipur district, Rajasthan. ![]() Hence introduction of controlled fracture growth technique has important role in development of marble extraction techniques. In addition to this micro cracks are developed in the remaining rock. ![]() Conventional drill and blast techniques have proven to be disadvantageous and have low recovery of blockable marble. Drilling is generally carried out by jackhammer but now a days compressed air operated hydraulic machines are coming into use. The principle objective of blasting is to develop cracks in the rock so as to dislodge it from the surrounding rock without causing damage to it or to the remaining rock. Blasting needs of marble is entirely different than conventional methods of blasting.
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