# Relationship history for MSHA mine 2900901

Current hierarchy: **Morton Carroll → White Rock Pumice Company → Caldwell 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:** White Rock Pumice Company → Caldwell Pit; 1989-05-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Morton Carroll → Caldwell Pit; 1989-05-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Morton Carroll → White Rock Pumice Company; 1989-05-01 to current/open; source msha-controller-operator-history