The plans involve extracting three million tonnes of coal, sandstone and fireclay from a site adjoining Druridge Bay, north of Morpeth, Northumberland.
More than 20,000 people have signed petitions claiming the mine would damage the environment, wildlife and tourism. Some residents support it.
Developer Banks Group promises extra jobs and investment.
Save Druridge Bay campaign organiser Lynne Tate said opponents were concerned about pollution, noise, traffic and the effect on wildlife.
Jobs could be lost in the "booming" local tourist industry, she said.
Banks said 50 jobs could be created at the site at Highthorn, south east of the village of Widdrington, with a further 50 transferred from its other sites in Northumberland.
It has reduced the size of its initial proposal and moved it further away from the village.
Some residents welcome the promise of new jobs, investment in community facilities and environmental improvements.
Jeanie Kielty from Banks Group said it proposed an "extensive package" of local benefits looking at wildlife, footpaths, cycleways, bridleways and tourism, leaving a "positive lasting legacy".
Northumberland County Council said all points raised at the meeting would be considered as part of the planning application.
A final decision is expected in June.
Hundreds of people have attended a public meeting about plans for opencast coal mining close to a nature reserve.