The changes address electrical equipment, diesel particulate matter and other requirements for underground mining operations.
Earlier research tested only medium-sized battery packs, and DOE said the study's findings could help inform emergency planning and occupational safety and health underground.
U.S. mines have now gone three years in a row without a pattern of violations notice, and operators can use MSHA's online calculators to track their own standing, the agency said.
Morton Salt said it is investigating the water intrusion with regulators and independent experts and will notify affected vendors and customers of what it calls a force majeure event.
More than $10.5 million will fund required instruction for new and experienced miners, with programs tailored to local hazards.
Health professionals and mining families raised concerns about dust exposure and access to disability benefits.