# Relationship history for MSHA mine 1507277

Current hierarchy: **Crown Central Petroleum Corp; JNO McCall Coal Company → Race Fork Coal Corp → No 2 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:** W R Grace & Company → No 2 Surface; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Race Fork Coal Corp → No 2 Surface; 1974-09-10 to 1977-04-21; source msha-controller-operator-history
- **controller_controls_operator:** W R Grace & Company → Race Fork Coal Corp; 1974-09-10 to 1977-04-21; source msha-controller-operator-history
- **controller_controls_mine:** Crown Central Petroleum Corp et al → No 2 Surface; 1977-04-16 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Race Fork Coal Corp → No 2 Surface; 1977-04-22 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Crown Central Petroleum Corp et al → Race Fork Coal Corp; 1977-04-22 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** JNO McCall Coal Company et al → Race Fork Coal Corp; 1977-04-22 to current/open; source msha-controller-operator-history