A scoping study is currently ongoing but Anglesey is now mulling whether a throughput of 1,000 tonnes per day rather than 500 tonnes would be more economic.
Using dense media separation, an ore sorting technique, would increase the effective daily production rate by about 40% with only a limited increase in capital.
That would mean a shorter mine life but potentially better returns. Construction of a larger processing plant with a higher throughput rate could also be justified on that basis even capital costs would be higher, Anglesey said.
Parys Mountain has indicated resources of 2.1mt of copper, lead, zinc but an inferred resource of 4.1mln tonnes, which can be upgraded with the development work and extend the mine life considerably said the junior.
Anglesey has now asked its scoping study consultants Micon and Fairport to consider alternative production and throughput scenarios of between 500 and 1,000 tonnes per day.
Modified mine production schedules and alternative capital cost estimates will arrive in the near future.
These will be incorporated into updated financial models, with an optimised development scenario available before the end of June.
Shares eased 3% to 4.26p.