Trump claims he will revive American coal companies and said in Sunday's debate that Democratic nominee Hillary Clinton wants to put the miners out of business. Clinton's plan focuses on shifting to clean, renewable energy.
"There is a thing called clean coal. Coal will last for 1,000 years in this country," Trump said during the debate.
Trump also wants to eliminate the Environmental Protection Agency's Clean Power Plan, which aims to reduce carbon emissions from coal-fired power plants. Ward supports the repeal of those regulations.
"We really think it should be a balanced energy position in the United States, with nuclear, gas and coal all playing a vital role, and we think the coal role could and should be bigger," he said.
The slide in coal began in late 2014, as low energy prices encouraged utilities to switch to burn cheaper natural gas. Coal exports have also been hurt by the strong U.S. dollar.
Ward said he expects to see a continued decline in its coal run rates in the coming quarters, but to a much lesser extent than what has occurred in the past.
"Over the last five years, we've went from $3.7 billion in coal revenue and we'll be at about $1.7 [billion] at this year. So we've lost over half our coal business."
— CNBC's Jacob Pramuk, Tom DiChristopher and Reuters contributed to this report.