Influence of Fluids on the Essential Parameters of Rotary Percussive Drilling   Louafi Messaoud Laboratoire d’Environnement (Tébessa) Université de Tébessa (Tébessa) Algérie (Algeria) e-mail: Lmessaoud@yahoo.fr
			ABSTRACT

The main objective of the work was to investigate the cutting efficiency with respect to drilling fluid composition by determining and comparing experimentally obtained values for specific energy and rate penetration. The description of a test rig for commercial rotary-percussion drills follows. The rig is equipped with several instruments for the continuous monitoring of the most significant drilling process parameters: blow frequency, rotation speed, drilling fluid flow rate, power and drilling speed.
The results of a test program that was carried out with a type GBH 8/65 DCE Bosch electrical rotary-percussion drilling machine on granite are finally reported and commented. It is considered quite encouraging that the performance of the machine investigated is comparable to those reported in the literature for conventional pneumatic and hydraulic drilling machines in dolomites, a rock that opposes a much lower resistance to rock breakage than granite.
The results thus analyzed demonstrate that to addition of certain reagents to the flushing always corresponds an increase in rock drill ability, with consequent increase in drilling rates of the rocks tested.

Keywords: Percussive drilling; Crushing; Specific Energy; Fluids; Efficiency

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