The company submitted a planning application to Cumbria County Council last month to extract coking coal off the coast of St Bees, with a processing plant on the former Marchon site at Kells.
Visitors to the open day can view more details about the project, which will be called Woodhouse Colliery, images of how the site might look and an estimated timeline.
People are being encouraged to talk to staff, ask questions and give feedback to help shape the project.
Helen Davies, communications manager, said: "We've said from the start we are committed to talking openly and honestly to everyone.
Helen Davies "We want to build something that people can really be proud of and we do want to hear all views."
The plan is for coal to be mined and moved via an underground conveyor to new processing and storage buildings on the old Marchon site. Processed coal will then be transported via a buried conveyor to new rail sidings in the Pow Beck Valley for loading onto trains.
Colin Sharpe, supply chain manager, said the proposed design of the site meant the coal and machinery would be undercover at all times and noise, light pollution and emissions would be carefully controlled.
The coal would be transported predominantly by rail and sea, either to UK steelworks or via Redcar Bulk Terminal to Europe.
The scheme will employ more than 500 people and bosses have pledged that at least 80 per cent of these positions will go to people living within a 20-mile radius of Whitehaven.
Offshore exploration is currently taking place, with a team of geologists working from a large jack-up barge off St Bees Head. The platform stands on the seabed, has living accommodation for up to 40 people and carries a drill used for collecting rock cores down to more than 600m below the surface, although the sea water depth is typically 20m to 25m.
The team aims to learn more about the geology and take samples for quality assessments, which will help with the detailed design of the mine layout.
WCM hopes to begin construction next spring, with coal production expected by the end of 2019.
A supplier open day will take place on July 12, when businesses and individuals can find out more about getting involved in the construction phase and beyond.
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