Not Your Grandfathers Mining Industry, Nova Scotia, Canada

Unexploded Dynamite

Two very unusual, yet strikingly similar, accidents took place at Nova Scotian gold mines in 1898. Historical accidents like them are partly why Nova Scotia’s mining and quarrying industry is so safety-focussed today. The industry has reduced its injury rate by 90% since the Westray inquiry report was released in 1997.

On the evening of Monday, July 25, 1898, Edward Spencer was working as an assistant to Sylvester Carroll, a drill operator at the Dufferin gold mine in Halifax County.

They were working on the sinking of a new vertical shaft by drilling holes into the rock so explosives, dynamite in this case, could be inserted. They would then trigger controlled explosions that broke the rock and deepened the shaft.

This was, and still is, standard activity in most mines and quarries. Blasts are done to break minerals and aggregate off a rock face and, in the case of a gold mine, the gold-bearing rock (ore) is hauled out of the mine and milled to separate the gold from its host rock.

There were two pairs of men working in the shaft, each pair using an air drill.

About 7:45 p.m., Carroll started a new hole using his 4-foot drill. It had gone in only a few inches when the rock into which he was drilling exploded.

Carroll was relatively lucky. Even though he was the one drilling the hole, he was only “slightly injured,” according to the Nova Scotia Department of Mines’ annual report for that year.

The Halifax Herald’s August 1 edition said Carroll, who was single and from Newfoundland, “received the contents of a rock in the left eye. He suffered some also from concussion of the brain, but will likely recover.”

It was Spencer who took the full force of the blast and died within hours. According to the Herald, “His head was severely mangled, and the body severely lacerated. Deceased survived six hours, though never conscious.”

Spencer was 27 years old and was “formerly a bandsman in the Queens Own regiment, highly respected and intelligent,” according to the newspaper. “Three years ago he purchased his release, and married a Miss Mosher from Harrigan Cove, this county. She is a sister of Geo. H. Mosher, lobster packer. She is prostrated by the shock.”

An investigation found that the same four men had been working Saturday evening, two days before the explosion, and a small bit of unexploded dynamite from one of the Saturday blasts remained in the bottom of a drillhole.

It was well-known that holes left behind from previous blasts could still contain unexploded explosives, which could be triggered if a miner drilled into them. For this reason, rules required that miners avoid drilling into old holes and always start new ones instead. Historical miners sometimes drilled into old holes anyway to save time and effort.

However, Carroll and Spencer followed the rules and did not drill into an old drillhole. Instead, they started a new hole near an old one. That was not unusual, and it was terrible luck that drilling a new hole somehow triggered unexploded dynamite in one of the holes they had drilled on the Saturday. The Department’s annual report suggested it was likely that the drill had strayed into the old hole where the remaining dynamite was located.

The Halifax Herald said an explosion caused by triggering unexploded dynamite was “something which does not occur once in a thousand blasts.”

“The Dufferin mine tragedy has caused a gloom of that district and the surrounding hamlets,” according to the newspaper.

A very similar accident occurred at Molega, Queens County, on Monday, September 12 that year. Robert Devaney and Clarence Boyer were drilling holes and doing blasts in the bottom of a shaft in the Parker-Douglas gold mine. They and two other men had also worked on the Saturday, firing five blasts and clearing out the broken rock.

On Monday morning – Sunday being a day off - they started drilling again and accidentally triggered unexploded dynamite from their Saturday blasts. Devaney and Boyer were both killed.

It could not be determined whether they had drilled into the old hole, or if the concussive force of drilling a new hole near an old one was enough to trigger the unexploded dynamite.

The Department’s annual report commented on how unusual it was for unexploded dynamite to be left in a drillhole: “Some things are always taken for granted, and one of them is that all the dynamite exploded if any does. This is the rule, and exceptions are too rare to be acted upon.”

The next day’s Evening Mail said the explosion “hurled rocks and earth in every direction. One of the men who were killed was terribly mangled, and was blown some distance away. A small building was wrecked by the shock. Details of the affair are meagre as yet.”

The Department’s annual report said, “Mr. Devaney was in charge; he was a careful man, and during a year, which for much of the time there had been more than fifty men at work, no accident had occurred. Mr. Boyer was a good miner, and not at all reckless. They were men of excellent qualities.”

Today, blasting is still an essential part of the mining process at most mines and quarries. Blasts are carefully designed to ensure they are as efficient as possible – so they use as little explosive and generate as little noise and dust as possible, while still freeing enough rock to meet operational needs.

They are also designed to ensure rock falls straight down, within a few metres of the blast, both for safety reasons and because it is more efficient for collecting material afterwards.

New technologies, such as digital blasting, have also made blasting more precise, allowing companies to reduce the amount of explosive they use.

In Nova Scotia, blasting cannot take place within 30 metres of watercourses and roads, and not within 800 metres of neighbouring buildings. This is the largest regulated blasting buffer distance in Canada.