BQE, which will also work to modernise the active Shangdong province operations' cyanide destruction and residue management, said the studies are part of a response to advancing environmental regulations. It will aid the companies in enabling the processing of feedstock with elevated levels of cyanide soluble copper.

Under the studies' outlines, BQE will complete the test work for metallurgical and wastewater treatability and then develop "a sufficient level of engineering" that will confirm the economics of the project as a whole, along with construction budget and implementation schedule.

BQE president and CEO David Kratochvil stressed that the new contracts with the unnamed Chinese miners were the result of the success of the water treatment plant designed and commissioned in 2018 at the Guoda gold smelter, which neighbours the operations.

"That project has made all the major metallurgical operations in Shandong province take notice of our capabilities," he said.

Asia vice president Songlin Ye at BQE Water added: "If these new projects move forward to implementation, we will be able to leverage our operations base at Guoda and our partnership with MWT, the Beijing-based company with construction capabilities we formed a joint venture with for the Guoda project, to build what would be the first SART [sulphidisation-acidification-recycling-thickening] application in China, and provide ongoing operations services to ensure performance excellence."

Worldwide regulations have been progressing to target not just residual cyanide by mining operations, but also to place limits for cyanidation and cyanide destruction by-products including ammonia, cyanate, thiocyanate and nitrite. The end goal is to ensure the non-toxicity of all discharges and negate impact to the receiving environment.

Last year, gold output in the Shandong province reached 120 tonnes (3.8 million troy ounces), or 30% of China's total gold production.