# Relationship history for MSHA mine 1508900

Current hierarchy: **Williams Companies Inc → Bell County Coal Corp → No 1 Surface**

- 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

- **controller_controls_mine:** Brown Mining Corp → No 1 Surface; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Brown Mining Corp → No 1 Surface; 1975-01-01 to 1975-04-30; source msha-controller-operator-history
- **controller_controls_operator:** Brown Mining Corp → Brown Mining Corp; 1975-01-01 to 1975-04-30; source msha-controller-operator-history
- **operator_operates_mine:** Bell County Coal Corp → No 1 Surface; 1975-05-01 to 1982-04-29; source msha-controller-operator-history
- **controller_controls_mine:** General Energy Corp → No 1 Surface; 1975-05-01 to 1982-04-29; source msha-controller-operator-history
- **controller_controls_operator:** General Energy Corp → Bell County Coal Corp; 1975-05-01 to 1982-04-29; source msha-controller-operator-history
- **operator_operates_mine:** Bell County Coal Corp → No 1 Surface; 1982-04-30 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Williams Companies Inc → No 1 Surface; 1982-04-30 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Williams Companies Inc → Bell County Coal Corp; 1982-04-30 to current/open; source msha-controller-operator-history