# Relationship history for MSHA mine 1510732

Current hierarchy: **Brassfield Fred & Dave Campbell → O K 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

- **controller_controls_mine:** Benjamin R.  Bennett → No 1 Mine; 1974-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** M & M Coal Company → No 1 Mine; 1977-09-01 to 1980-07-14; source msha-controller-operator-history
- **controller_controls_operator:** Benjamin R.  Bennett → M & M Coal Company; 1977-09-01 to 1980-07-14; source msha-controller-operator-history
- **operator_operates_mine:** Blue Ridge Mining Company → No 1 Mine; 1980-07-15 to 1980-10-14; source msha-controller-operator-history
- **controller_controls_mine:** Smith Harley → No 1 Mine; 1980-07-15 to 1980-10-14; source msha-controller-operator-history
- **controller_controls_operator:** Smith Harley → Blue Ridge Mining Company; 1980-07-15 to 1980-10-14; source msha-controller-operator-history
- **operator_operates_mine:** O K Coal Company → No 1 Mine; 1980-10-15 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Brassfield Fred & Dave Campbell → No 1 Mine; 1980-10-15 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Brassfield Fred & Dave Campbell → O K Coal Company; 1980-10-15 to current/open; source msha-controller-operator-history