Two B.C. unions that filed for a judicial review of a mining company's case to bring temporary workers from China to a project near Tumbler Ridge say they have new evidence the company never intended to hire Canadians at the mine.

The International Union of Operating Engineers Local 115 and the Construction and Specialized Workers Union Local 1611 said a new document shows HD Mining did not in fact plan to use a mining technique it claimed Canadians are not familiar with.

The company said it intended to use the so-called long-wall technique to harvest coal from its Murray River mine and insisted the Chinese workers were needed for their specialties in the use of it.

The company was granted permits for 201 workers from China under the Temporary Foreign Worker Program.

But according to documents obtained by the union, HD Mining's application to the B.C. Ministry of Natural Resource Operations in June 2011 shows during a two-year bulk sample collection period the company had no plan to employ the long-wall technique.

"The evidence we have is taken from the Work Permit Application that HD filed with the Ministry of Natural Resource Operations, and which indicates that the bulk sample will be taken by traditional 'room and pillar' mining," said Charles Gordon, counsel for the two unions, in an email.

Gordon said the unions filed the evidence in court Monday and HD Mining has until Friday to respond.

After winning a court decision to have resumes of 300 Canadians who applied for the positions handed over to them, unions have accused the company of turning down fully qualified Canadians for the jobs.

They alleged the company only wanted to bring in Chinese workers so they could pay them less and not worry about health and safety issues on the job.

Shortly after the resumes were disclosed, HD Mining sent 16 miners already at the site back to China, blaming delays and litigation costs related to the unions' court action.

Meanwhile, the B.C. Federation of Labour has launched a new radio ad it said takes aim at the federal government for granting the company the permits to bring in the Chinese workers.

But media reports have said the B.C. Liberals have been critical of the ad, claiming it isn't clear and meant to blame them for the decision to allow the workers in.

Freelance reporter Jeremy J. Nuttall has been covering Temporary Foreign Workers Program issues related to mining in The Tyee. Find his previous stories here.