# Relationship history for MSHA mine 0800520

Current hierarchy: **Des Rocher M A → Des Rocher Sand & Rock → Pompano Pit**

- 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:** Davie Des Rocher Sand Company Inc → Pompano Pit; 1950-01-01 to 1985-04-17; source msha-controller-operator-history
- **controller_controls_mine:** Mc Govern Hal E → Pompano Pit; 1950-01-01 to 1985-04-17; source msha-controller-operator-history
- **controller_controls_operator:** Mc Govern Hal E → Davie Des Rocher Sand Company Inc; 1950-01-01 to 1985-04-17; source msha-controller-operator-history
- **operator_operates_mine:** Des Rocher Sand & Rock → Pompano Pit; 1985-04-18 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Des Rocher M A → Pompano Pit; 1985-04-18 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Des Rocher M A → Des Rocher Sand & Rock; 1985-04-18 to current/open; source msha-controller-operator-history