Wolf Minerals (LON:WLFE) has shipped its first batch of tin concentrate from the Hemerdon mine in Devon.
Tin is a by-product of the operation with tungsten the main metal being mined.
A ramp up to full tungsten production, however, has been hampered by more problems at the processing plant.
Wolf said it is working with the plant contractor, GRES, to get the plant running smoothly after a recent test highlighted recovery and product grade issues as well as a need for better access to equipment and environmental improvements.
As a result of the plant's underperformance Wolf has undershot a supply commitment to major customers and discussions are underway over how to make the shortfall any potential penalty.
A rise in the price of tungsten recently has given the miner a boost.
Prices for tungsten concentrates follow the same trend as prices for ammonium paratungstate (APT), said Wolf, a key intermediary product in the tungsten supply chain.
APT prices recently have rallied to US$200/mtu from US$172/mtu in the first three months of 2016.