# Relationship history for MSHA mine 0502477

Current hierarchy: **Cardium Service & Supply Ltd → Colorado Silica Sand Inc → Chapel Hills 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:** Fountain Sand & Gravel Company → Chapel Hills Pit; 1950-01-01 to 1984-12-19; source msha-controller-operator-history
- **controller_controls_mine:** Crane Company → Chapel Hills Pit; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Crane Company → Fountain Sand & Gravel Company; 1950-01-01 to 1984-12-19; source msha-controller-operator-history
- **controller_controls_mine:** Cardium Service & Supply Ltd → Chapel Hills Pit; 1978-03-09 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Colorado Silica Sand Inc → Chapel Hills Pit; 1984-12-20 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Cardium Service & Supply Ltd → Colorado Silica Sand Inc; 1984-12-20 to current/open; source msha-controller-operator-history