Commission sets standards for reopening of Omai gold mine

The Guyanese government’s Commission of Enquiry into last summer’s effluent spill at the Omai gold mine has called for several modifications to the tailings dam. It has also recommended a regular program of testing and inspection for Omai and any future mining operations.

The commission, headed by former Chancellor of the Judiciary Kenneth George, delivered its report to the government in early January, recommending that the mine be permitted to resume production.

The operation, owned 65% by Cambior (TSE), 30% by Golden Star Resources (TSE) and 5% by the government, has been closed since mid-August, when the dam failed. About 3 million cu. metres of waste process water, containing 28 parts per million cyanide, flowed into the Omai and Essequibo Rivers.

The George Commission’s report stipulates that, before production can resume, the new tailings pond must be examined and approved by an independent geotechnical consultant. The mine will be allowed to treat and discharge waste water, provided Omai adds four components to its wastewater process: a hydrogen peroxide oxidizer, activated carbon strippers, a multiport aerator and a clarifier. The first three systems destroy cyanide or remove it from the waste water, while the last removes suspended solids.

More sweeping was the report’s recommendation that the government introduce environmental protection legislation to govern the country’s industries. The legislation would establish a regulatory agency with legal power to enforce environmental standards, a laboratory service to supply the agency with technical backup, and a national disaster response agency. To ensure compliance, the commission called for regular testing of Omai’s process waters, its effluent, and the waters in nearby rivers.

It also suggests the government and Omai Gold Mines should take measures to give the public “a sensible and rational understanding of cyanide and its effects.”

Under the measures prescribed by the report, the Omai mine would have to prepare a closure plan, similar to those now submitted by the developers of new mines in Canada, providing for mine-site reclamation and disposal of hazardous materials. Linked to this is a recommendation that Omai should be obliged to clean up the failed tailings pond and post a bond over and above the current US$500,000 as surety against future cleanups.

The commission did not find criminal liability on the part of Omai’s owners or contractors, saying in its report that “because of the amount of water and slurry remaining in the pond, it is uncertain at what stage or stages of the dam’s construction the faulty work took place . . . and therefore difficult to fix liability.” It found that the dam’s armor stone — broken rock placed on the downstream side of the core to give it structural stability — had not been built to its specified design, allowing the fine-grained material in the core to fail.

Two Canadian geotechnical firms — Knight Piesold of Vancouver, B.C., and Golder Associates of Mississauga, Ont. — were engaged to design and supervise the dam project. Knight Piesold has stated publicly that it believes the failure started in a part of the dam built after it was no longer on site. Golder officials, too, are taking the position that their firm is not liable, noting that Cambior has retained Golder for the design and construction of the new tailings pond.

The commission did find that Omai Gold Mines was liable for bringing cyanide on to the site and subsequently releasing it into the environment; damages that were a direct result of the release would therefore be actionable. It refused to find the company liable for damages incidental to the release, such as loss of employment.

The government-backed newspaper Guyana Chronicle reported that the opposition Working People’s Alliance had criticized the George Commission for not recommending a full environmental audit and for not condemning the companies for negligence. The WPA also said the government should increase its ownership level in the Omai project and insist on “zero discharge” of cyanide.

Cambior has already started work on the new tailings pond and believes Omai can be ready to go back into production by the end of January. Henry Roy, Cambior’s chief financial officer, says the company was still reviewing the commission’s recommendations but that, at first glance, “most of the other recommendations are things we can manage.”

He expects the costs of meeting the conditions will be close to what the company had predicted in earlier statements, including US$2-3 million for the water treatment system and under US$1 million for civil liabilities.