The labour dispute at Windsor Salt is entering its fourth week with no end in sight.
Unionized workers have been off the job since February 17 to back contract demands.
The 250 workers are represented by Unifor Local 1959 and Local 240.
Local 1959 president Bill Wark says no new talks are planned.
The company and the locals have not returned to the bargaining table since talks broke off.
Last month, the union said negotiations are at a standstill as the company's representatives refuse to discuss any monetary items without agreements from the union to allow widespread contracting out of union jobs.
Workers impacted by the strike are in the office, the Ojibway Mine and the evaporation processing fields.
This round of bargaining is the first since Windsor Salt was purchased by U.S. based Stone Canyon Industries.
The Ministry of Labour Immigration, Training and Skills Development is investigating a "complaint" at the Windsor Salt mine.
According to CTV Windsor, officials won't divulge the nature of the complaint and will only say it was received on Mar. 8, 2023.
An inspector has been assigned to the investigation and officials declined to comment until that work is complete.