# Relationship history for MSHA mine 1511178

Current hierarchy: **Burns Billy R--Charles Marcum → B & M Coal Company → No 2 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:** Burns Billy R--Charles Marcum Et Al → No 2 Mine; 1977-11-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** B & M Coal Company → No 2 Mine; 1978-04-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Burns Billy R--Charles Marcum Et Al → B & M Coal Company; 1978-04-01 to current/open; source msha-controller-operator-history