Single Wall Emulsion Liner
LOCATION: Diavik, Northwest Territories SCOPE OF WORK: Manufacture and supply 15" x 100' 8mil emulsion liner PROJECT PARTNERS: Owner: Diavik Diamond Mines
The Diavik Diamond Mine is located on a 20 square kilometre island, informally called East Island, in Lac de Gras. Naturally with the vast amounts of water surrounding the mine, the geology is particulalry wet and blast holes are too wet to pump, so a 100% waterproof emulsion is used and the
use of poly blast-hole liners is abandoned. However, in Diavik’s case the rock bed geology is filled with a multitude of fissures & crevices, causing all of the emulsion being pumped into the blast-hole to be lost in the geology – not only an issue in keeping up with the strict environmental regulations on site, but also a very expensive proposition. Other challenges faced included the -40 ºC temperature, and the issues of water filled holes posing extreme challenges in getting a liner down a blast-hole.
Layfield manufactured and supplied an emulsion liner which was used to contain the emulsion, so blasting could be carried out. Normally when 100% emulsion is used in mining blast-hole liners do not typically get used, but ironically in this application the two work in unison to carry out the blasting process. During the initial trial, 38 out of 41 holes basted in the initial test shot were lined with the emulsion liner, according to the Diavik Blast Supervisor. The liners were pre-sleeved onto plastic pipes and the pipes were then mounted off the powder truck’s hose pulley. The emulsion hose, booster and primer line were then forced thru the pipe and down into the blast hole. On occasion it was noticed that the liner must have ruptured during the emulsion loading. The rupture happened at some point when the liner was being forced down into the blast hole. Rough hole walls would have caused the liner to rip, and then when the emulsion was injected the tear would have continued to split. Given an emulsion is being used, there is only a minor concern if some of the liners failed. Diavik figures that the majority of the failed liners in those circumstances were still preventing most of the emulsion from flowing into cracks in the blast hole walls. A thicker gauged liner was considered as this would help reduce the occurrences of tears, however the trade off is that a thicker gauge plastic liner would make it far more difficult to pre-load on the PVC pipe. It was finally determined that an 8 mil liner would be suitable, as
this would provide the balance between material strength required for down hole survivability, and the flexibility needed to manipulate the liner during loading.