The Trexatians were eventually able to find a supply of the ore on Repok, a neighboring planet. Unfortunately, the planet was inhabited by the Repoki, and the Trexatians had no choice to raid the planet for the ore, despite signing an agreement with the United Federation of Planets.
While the initial raids were quite subtle in their execution, the Repoki soon discovered the loss, as they mined vadinite for themselves as it was a source of currency on Repok. Soon after, all-out war broke between the Repoki and the Trexatians. (TNG novel: Resistance)