# Relationship history for MSHA mine 1515955

Current hierarchy: **Davidson Charles → Davidson Coal Company → No 1 Mine**

- 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:** Davidson Coal Company → No 1 Mine; 1987-03-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Davidson Charles Et Al → No 1 Mine; 1987-03-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Davidson Charles Et Al → Davidson Coal Company; 1987-03-01 to current/open; source msha-controller-operator-history