World record for raiseboring - Atlas Copco

PRODUCTS & PROGRESS >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>New hammer for an unusualapplication: Jimmy Hallberg(left) and Krister Iveblad withthe QLX50 at the site of thenew “green”power plant inKarlskrona, Sweden.NEW HAMMERfor deep hole DTH drillingAtlas Copco has developed a new DTH (down-the-hole) hammer for deep holedrilling which promises substantial improvements compared with previous models.Called QLX50, the hammer is currently being field tested at several sites and thepreliminary results are encouraging.Based on the successful TD50, theQLX50 represents a new, improvedhammer concept especially intendedfor 130-150 mm diameter deep hole applicationssuch as water wells and geothermaldrilling. The hammer features a two piecetop sub and an improved check valve withthe casing and piston designed to operate ata pressure of up to 35 bar.To gain superior drilling economy it ispossible to rebuild the hammer when theexternal parts have been worn out. Thisrebuild economy kit consists of casing,chuck, back head, o-ring kit and a QLsustainability kit. The conversion fromworn to “as new” will take 30–60 minutesonly. As a result, the drill meters of twohammers can be obtained for the price ofone-and-a half QLX50.Test drilling is currently being conductedat sites in Scandinavia and the USA. Oneof these, near Karlskrona, Sweden, involves100 holes which will be used to cool downthe turbine and generator at a new CHPplant (Combined Heat and Power), burningrenewable biomass fuel from the forestry andsawmill industries. This will give substantialenvironmental improvements by reducing 80percent of the greenhouse gases.Drilling is being performed in hardgranite containing fractured zones and withup to 15 m of overburden and a maximumhole depth of 200 m.Skånska Energi Borrning AB was chosento drill the holes and Jimmy Hallberg,Project Manager, says: “The area where wewere drilling was 100 by 60 meters. Someholes were dry whereas others had a waterinflux of up to 1 200 litres per minute. Wechose Atlas Copco Secoroc 140 mm bitswith the concave front design. The 16 mmbuttons worked extremely well and the penetrationrate, averaging 25 to 30 m/hr in veryhard granite, was higher than expected.”Krister Iveblad at Atlas Copco, whosupervised the drilling throughout the5 000 m test, now expects that the economykit will give the contractor another 5 000 mof problem-free drilling. 1The QLX50 DTHhammer, as seenat the recentConAgg Expotrade show inLas Vegas.MINING & CONSTRUCTION – 1 / 2011 25