Union employees at US-based Stillwater Mining have rejected a proposed four-year contract for 900 workers that may lead to a reduction of their pay.
According to Stillwater, the United Steel Workers International Union employees at its Stillwater Mine and Columbus processing facility are represented by the USW International Union Local 11-0001.
The union's negotiating committee and the representative for USW unanimously recommended that their members approve the tentative agreement, the company said.
Stillwater Mining president and chief executive officer Mick McMullen said: "We are disappointed that the tentative agreement was not ratified.
"Based on this decision by the union members, company management is considering all alternatives to create a situation that will best promote the long-term economic viability of operations at the Stillwater Mine and Columbus processing facility."
Stillwater said that it will find a reasonable solution for all stakeholders by working with the committee for the union and the representative.
In May, the company reached a tentative agreement with the union on the terms of a new labour agreement at its processing facility.
At that time the committee for the union and the representative for USW recommended approval of the agreement to members of the United Steel Workers Local 11-001.
Stillwater produces platinum group metals (PGMs) outside of South Africa and the Russian Federation.
PGMs are used in range of applications, including automobile catalysts, fuel cells, hydrogen purification, electronics, jewelry, dentistry, medicine, and coinage.