A Canadian combat engineer describes seeing smoke and a blast when the vehicle he was driving struck an explosive device near Kabul. He escaped injury in the incident.

Sgt. Rene Grignon, 38, was driving a Zettelmeyer front-end loader equipped with a bucket on a heavily-mined track near the Afghanistan capital Wednesday, when it was stopped by the explosion.

"I happened to hit something, and the vehicle all of a sudden came to a stop," Sgt. Grignon told CTV Newsnet. "I saw smoke and I saw a blast."

Grignon and other Canadians were carrying out an intensive mine-clearing operation aimed at reopening the sector to Canadian patrols.

"There were some engineers out in front of the vehicle doing a visual inspection of the track. The vehicle itself was scraping behind them" when the incident occurred Canadian Press reporter Stephen Thorne said.

Grignon, a heavy equipment supervisor and operator with 24 Field Squadron, is a native of Rouyn-Noranda, Quebec. He was not injured in the blast. But he was taken to a field hospital at nearby Camp Julien for observation.

The 30-tonne vehicle sustained some damage, including a tire blown at least six metres from the Zettelmeyer. Military officials said the loader could be repaired.

Grignon says he is undaunted by the experience.

"My heart didn't race," he said in an interview. "I always wanted to be in that piece of equipment and have something go off to prove that it is a safe piece of equipment."

An investigation is underway to determine whether the explosion was caused by a mine, or other explosive device.

The incident happened at 12:35 p.m. local time, on the same route where two Canadian soldiers were killed by at least one anti-tank mine Oct. 2.

Sergeant Robert Short and Corporal Robbie Beerenfenger were killed and three others injured when their vehicle struck an explosive device on the track about 3.5 kilometres southwest of the main Canadian base in Kabul.

The soldiers were patrolling in a lightly-armoured Iltis vehicle. In Canada, the incident sparked a national debate about its suitability to the Afghan mission.

A board of inquiry is still investigating that blast.

Sgt. Grignon says efforts are being made to ensure no more lives are lost -- and this incident was just part of that job.

"With all the attention to this, we are trying our best to make the road safer for our infantry," Grignon said. "And in doing such we encountered this."

Canadian troops are deployed in Afghanistan, making up the largest portion of the 31-country International Security Assistance Force (ISAF) created by the United Nations in December 2001.

ISAF is charged with stabilizing the troubled country's capital, Kabul, and also acting as a bulwark for the interim government of President Hamid Karzai.

The only other Canadian deaths in the Afghan operation occurred in April 2002. Four Canadian soldiers were killed when a U.S. F-16 fighter jet mistakenly bombed their position during a live-fire training exercise near Kandahar.

Today's incident comes on the same day defence minister John McCallum is expected to announce the multi-million-dollar purchase of another controversial combat vehicle -- the so-called Stryker.

In a report five years ago, the military concluded the eight-wheeled, 18-tonne, lightly armoured vehicle equipped with a 105-mm cannon would be a poor choice to replace Canada's aging tanks.

But McCallum is expected to announce Ottawa will buy 60 of the Canadian-made vehicles.