Troubles continue to delay the first horizontal drilling and fracturing operation in the north.

ConocoPhillips is drilling two horizontal holes 20 kilometres southwest of Norman Wells, N.W.T. It plans to hydraulically fracture -- pump a mix of sand and chemicals down the holes under high pressure -- multiple times this winter.

The first of those fracks was to happen on Feb. 10. But last week 2700 cubic metres of fresh water that was to be used to make the fracking mix spilled from a retention pool. That is enough water to fill an Olympic-sized swimming pool.

There have also been two minor waste water spills at the site.

One hundred and fifty litres of partially treated sewage water spilled from a vacuum truck on Jan. 31. According to a spill report it was all cleaned up with the vacuum truck, with no environmental damage.

Three days later 240 litres of untreated sewage spilled when a sewer line got blocked by a cleaning rag, causing an overflow. The company reports that 90 per cent of the sewage was cleaned up.

The spills come after an injury at the site in mid-December. A worker was reportedly flown to hospital after sufferning a back injury when a winch cable broke.