CASPER, Wyo. (AP) — Projections show that a decline in coal leasing could tighten up funding for school construction in Wyoming in a few years.

Fees paid by coal companies to lease federal coal in the Powder River Basin have financed more than $1 billion in school construction in Wyoming over the past decade.

Leasing has dwindled, however, as demand for coal has declined. Back-to-back unsuccessful bids on coal-rich lands resulted in no new coal leases in Wyoming last year.

Economists now project that Wyoming's share of federal coal-leasing fees known as coal lease bonuses could hit zero in 2018.

State Sen. Bill Landen of Casper says if significant new leasing doesn't happen soon, Wyoming will need to change how it pays for new schools and school renovations.