# Relationship history for MSHA mine 3400972

Current hierarchy: **Burwell C L → B & C Rock Inc → B & C Quarry And Plant**

- 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:** F & M Corp → B & C Quarry And Plant; 1950-01-01 to 1978-04-24; source msha-controller-operator-history
- **controller_controls_mine:** F & M Corp → B & C Quarry And Plant; 1950-01-01 to 1978-04-24; source msha-controller-operator-history
- **controller_controls_operator:** F & M Corp → F & M Corp; 1950-01-01 to 1978-04-24; source msha-controller-operator-history
- **operator_operates_mine:** B & C Rock Inc → B & C Quarry And Plant; 1978-04-25 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Burwell C L → B & C Quarry And Plant; 1978-04-25 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Burwell C L → B & C Rock Inc; 1978-04-25 to current/open; source msha-controller-operator-history