Opponents and supporters of Dominion Virginia Power’s proposed coal-fired power plant in southwestern Virginia are expected at a public hearing in Richmond tomorrow. The State Corporation Commission will determine whether to issue a permit for the $1.6 billion plant in Wise County. Plans call for a 585-megawatt plant that will use clean-coal technology and burn only coal mined in Virginia. Environmentalists say the promised technology doesn’t exist. They also fear environmental damage from increased strip mining in the state. Supporters, including many county officials, say they trust Dominion to make good on its promise to use clean-coal technology. They also say the plant would be an economic blessing to the job-starved county.