# Relationship history for MSHA mine 3607908

Current hierarchy: **Mid-American Waste Systems Inc → National Waste & Energy Corp → Valley Coal**

- Valid-time bounds: inclusive, date granularity
- Null end: open-ended in the upstream history row; not independent proof of present control
- Transaction-time observation: 2026-10-13T11:19:05.459773+00:00

## Valid-time edges

- **operator_operates_mine:** National Waste & Energy Corp → Valley Coal; 1992-02-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Mid-American Waste Systems Inc → Valley Coal; 1992-02-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Mid-American Waste Systems Inc → National Waste & Energy Corp; 1992-02-01 to current/open; source msha-controller-operator-history