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Title: Optimizing rotary drill performance

Data is presented showing Penetration Rate (PR) versus Force-on-the-Bit (FB) and Bit Angular Speed (N). Using this data, it is shown how FB and N each uniquely contribute to the PR for any particular drilling situation. This data represents many mining situations; including coal, copper, gold, iron ore and limestone quarrying. The important relationship between Penetration per Revolution (P/R) and the height of the cutting elements of the bit (CH) is discussed. Drill performance is then reviewed, considering the effect of FB and N on bit life. All this leads to recommendations for the operating values of FB and N for drilling situations where the rock is not highly abrasive and bit replacements are because of catastrophic failure of the bit cone bearings. The contribution of compressed air to the drilling process is discussed. It is suggested that if the air issuing from the bit jets is supersonic that may enhance the sweeping of the hole bottom. Also, it is shown that not just uphole air velocity is enough to provide adequate transport of the rock cuttings up the annulus of a drilled hole. In addition, air volume flow rate must be considered to assure there is adequate particle spacingmore » so the mechanism of aerodynamic drag can effectively lift the cuttings up and out of the hole annulus.« less
Authors:
 [1]
  1. Drilling Technologies, Richardson, TX (United States)
Publication Date:
OSTI Identifier:
400819
Report Number(s):
CONF-950247--
TRN: IM9650%%225
Resource Type:
Conference
Resource Relation:
Conference: 21. annual conference on explosives and blasting techniques, Nashville, TN (United States), 5-9 Feb 1995; Other Information: PBD: 1995; Related Information: Is Part Of Proceedings of the twenty-first annual conference on explosives and blasting technique. Volume 2; PB: 345 p.
Publisher:
International Society of Explosives Engineers, Cleveland, OH (United States)
Country of Publication:
United States
Language:
English
Subject:
42 ENGINEERING NOT INCLUDED IN OTHER CATEGORIES; 01 COAL, LIGNITE, AND PEAT; ROTARY DRILLS; PERFORMANCE; EXPLOSIVE FRACTURING; ROCK DRILLING; COAL MINING; SERVICE LIFE; DRILL BITS; CUTTINGS REMOVAL