WorldWide Drilling Resource

Exceptional Performance and Diversity Adapted from Information by Foremost It was June 1996, when a tourist spotted a sinkhole on the crest of Canada’s W.A.C. Bennett earthen dam in northern British Columbia. Since this dam, built in the 1960s, retains one of the largest reservoirs in the world, extra care had to be taken when figuring out what to do to correct the problem. Although imme- diate repairs were necessary to avoid catastrophe, nothing was al- lowed to penetrate the fragile formation - not compressed air, water, or drilling mud - for fear the pressure would cause the dam to fracture. The main contractor, Hayward Baker, approached Foremost Industries and a few of their customers to develop a drilling method to repair the 23-foot void in the dam. Foremost devel- oped an air lift auger system which would permit drilling down to consolidated earth while not allowing anything to escape into the ex- isting formation. The only rig al- lowed on-site was the Foremost DR24 drill. There were a total of six drills operating at the dam at one point. Once the cased auger sys- tem reached the undis- turbed consolidated formation, which at its deepest spot was about 350-400 feet, the inner drill string was removed. At this point, a controlled pressure grouting system was installed and the casing was retracted two inches at a time until the void was finally filled and the integrity of the dam was once again secure. The DR 24 has been in continuous service since the late 1970s. Originally developed for the water well and explo- ration markets, this unique rig has since found additional applications in placer sampling, environmental drilling, and the construction foundation market. It has proven itself repeatedly in some of the toughest unconsolidated overbur- den formations. Since the DR can drill without fluids, loss circulation and aquifer cross contamination are minimized. As with all Foremost drills, DR rigs are backed by the company’s knowledgeable team of experts providing superior cus- tomer support. In fact, the company has one of the largest engineering departments in the industry. ) )/, /-.)' ,- )- . , # ( # 2 )- )1 , 2 )- )1 , .),' ( /,,$ ( ) - - ( $ , . ) 2 1 && )(-. (.1 . , )' )(-. (. . , .$0 . - /.)' .$ &&2 1$.# .# &)-- )! *)1 , .) *,)0$ " &&)(- )! *, --/,$3 1 . , .) 0 ,2 -#)1 , .)$& . ( -$(% ) ( , .), +/$, 1 ( /-.,2 ,) / . $- )/(.- 0 $& & !), $-.,$ /.),- ( $(-. && ,- 48 SEPTEMBER 2016 WorldWide Drilling Resource ®