Impala Canada, SCR Mines Technology fined $430,000 after worker killed by muck at palladium mine

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Impala Canada and SCR Mines Technology have been fined a total of $430,000 after a worker was killed on the job in 2020.

The fine comes after OHS Canada reported just this week that Impala Canada had also been fined $50,000 after a worker was injured in a fall from a scissor lift.

In this case, the worker was fatally injured when blasted ore, saturated with concrete and water, overwhelmed protective barriers at the base of a mining shaft used to transfer ore and mining waste from the Lac Des Iles Mine near Thunder Bay, Ont.

Following a guilty plea in Provincial Offences Court, Impala Canada Ltd was fined $300,000 and SCR Mines Technology (2013) Inc. was fine $130,000. The court also imposed a 25 per cent victim fine surcharge as required by the Provincial Offences Act. The surcharge is credited to a special provincial government fund to assist victims of crime.

What happened

In 2019, Impala Canada Ltd. found deterioration in an ore pass at the Lac Des Iles Mine. An ore pass is a near-vertical underground opening designed to allow blasted ore, referred to as “muck” to flow from one area of a mine to another. Muck travels through ore passes by tumbling and sliding along the pass. Over time, ore pass walls can become damaged and enlarged, allowing the surrounding rock to fail and fall into the pass, which can negatively affect mine production.

Impala Canada Ltd. retained SCR Mines Technology (2013) Inc. (SCR), an ore pass rehabilitation specialist company, to repair the ore pass.

SCR’s process for rehabilitation involved slowly working down the ore pass, progressively scaling the walls and installing ground support, followed by shotcreting (concrete sprayed with water at high speed onto a surface through a hand-held nozzle) the supported area in six-foot vertical sections. The ore pass was accessed by a pneumatic elevator running along the ore pass on a track fixed to the walls (an Alimak).

SCR was allocated control of the ore pass for the repair work after an Impala Canada Ltd. worker locked out the loading pocket. When the muck pile was drawn down at the loading pocket, SCR employees would remove its locks from the equipment, and the Impala Canada Ltd. worker would pull material from the ore pass by operating a guillotine gate intended to control the flow of the muck.

Before beginning the work, SCR employees filled the ore pass with muck to provide a stable working platform and to stabilize the ore pass walls. The employees stood on the muck while tied off to the Alimak to install the ground support and shotcrete the ore pass walls. Once a section of wall was repaired, the SCR employees exited the ore pass and muck was evacuated from the ore pass from below by Impala Canada Ltd. worker operating a pneumatic gate. The evacuation of muck exposed the next six-foot section of the wall.

After reinstituting the lockout of the loading pocket, the SCR employees would re-enter the ore pass via the Alimak and continue repairs to the next section. This process would be repeated until the ore pass was fully repaired.

Unusual amount of ‘shotcrete’

Between May 23 and May 27, 2020, SCR employees observed that an unusual amount of the shotcrete was rebounding off the walls and landing on the muck floor. They further observed water resting on top of the muck, and that the water would disappear when the muck was drawn down and evacuated from the ore pass.

On May 27, 2020, SCR began a draw down of muck to expose the next section of the ore pass wall. Three skips of material were removed but did not lower the muck pile as much as expected. This may have indicated a hang up, but the SCR workers at the ore pass saw the muck pile draw down. The SCR crew determined that a further draw down of muck was needed to fully expose the next section of the ore pass wall.

An SCR worker entered the loading pocket platform at the bottom of the ore pass, to remove the lockout locks so that the additional muck could be evacuated. The worker, communicating with colleagues at the top of the ore pass with a radio advised there was some trouble getting the muck to come down the ore pass to the skip. Very shortly after, the muck dropped suddenly.

At the loading pocket, the flow of muck was not controlled by the guillotine gate, which the Impala Canada Ltd. worker had closed. This muck had a large content of saturated shotcrete and it overwhelmed the protective barriers at the base of the ore pass, fatally injuring the worker.

Regulations

Section 5.1(2) of Ontario Regulation 854/90 requires an employer to conduct “a risk assessment (that) must take into consideration the nature of the workplace, the scope of the work, the conditions of the work at that workplace and the conditions of work common at similar workplaces.”

In this case, that risk assessment should have considered the location and placement of SCR personnel during the muck draw down activities that could pose a danger to workers. SCR Mines Technology (2013) Inc. failed, as an employer to comply with the requirements of the regulation, contrary to section 25(1)(c) of the Occupational Health and Safety Act.

At the time of the incident, the Lac Des Iles Mine had an underground water management plan in place to protect the underground workings of the mine against inflows and accumulations from mine process water and surface water. The plan provided for several procedures, because the mine’s ore passes are typically dry, the plan did not include procedures to guard against the addition and accumulation of water in ore passes related to repair activities.

Section 87.1(2)(c) of Ontario Regulation 854/90 requires that, “an owner of an underground mine shall…develop and maintain a written water management program” and “…the program shall include measures and procedures to…prevent unwanted or uncontrolled flows of water in all areas of the mine,” including ore passes.
Impala Canada Ltd. failed to ensure that the measures and procedures prescribed by the regulation (section 87.1(2)(c) of the Mines and Mining Plants Regulation) were carried out in the workplace, contrary to section 25(1)(c) of the Occupational Health and Safety Act.