 Moodys Investors Service Moodys affirmed all ratings for Natural Resource Partners L.P., including the B2 Corporate Family Rating CFR, and revised the rating outlook to negative from stable. NRP has repaid more than half of its debt since 2015, but substantive deterioration in coal industry fundamentals will reduce cash flow generation and slow the pace of debt reduction in 2020, said Ben Nelson, Moodys Vice President -- Senior Credit Officer and lead analyst for Natural Resource Partners L.P. 