Electrical equipment certification in Canadian underground coal mines – problem solved?

Résumé

Certification of electrical equipment for underground coal mines in Canada is problematic. EX protected electrical distribution equipment to Group 1 standards is not manufactured in Canada, and even if it were, there is no facility in Canada which is accredited to certify it. The Canadian Federal laboratories previously tasked with the job are closed. Provincial regulations require certification by either a now-defunct facility or by the US authorities (MSHA). Unfortunately the underground coal legislation in the US is significantly at odds with Canadian Provincial legislation and equipment approval requirements which presents problems with equipment certified there.

Although the underground coal mining industry in Canada is small, the western Provinces are blessed with substantial resources of high quality steel-making coal, much of which can only be accessed by underground mines. There are perhaps half a dozen large underground projects awaiting a price revival in Alberta and British Columbia, and it was the authors’ experience at one of these projects which lead to this paper.

The project in question was owned by a Chinese company which wanted to use Chinese electrical distribution equipment certified in China to IEC equivalent standards. The process of convincing the Provincial regulators that the Chinese equipment was safer than the equipment which would be allowed under Canadian standards was arduous but ultimately successful. The next step was to seek changes in the Canadian electrical standard applicable to mines so that the benefits could be felt across the country.  This has recently also been accomplished.

This paper examines the problem through an important aspect of electrical safety in underground coal mines - protection against electric shock and arcing. It compares the requirements of the Canadian legislation, US and UK legislation and IEC standards used by other countries.

It concludes that the levels of safety against shock and arcing afforded by IEC-certified multi-point systems can be orders of magnitude better than the single point systems mandated or traditionally used in Canada. Additionally, multi-point systems may be better suited to protect high voltage equipment beginning to be deployed in large open pits than the current Canadian protection standards. The recommendations arising for changes to Canadian standards await ratification, and we are hopeful that they will be adopted by Provincial regulators as soon as practicable.