# Relationship history for MSHA mine 0300240

Current hierarchy: **Kemp Roy L → Kemp & Son Stone Company → Kemp & Son Stone Company**

- Valid-time bounds: inclusive, date granularity
- Null end: open-ended in the upstream history row; not independent proof of present control
- Transaction-time observation: 2026-10-17T05:35:58.500035+00:00

## Valid-time edges

- **operator_operates_mine:** Sunset Stone Company → Kemp & Son Stone Company; 1950-01-01 to 1990-10-23; source msha-controller-operator-history
- **controller_controls_mine:** Goodson Hugh → Kemp & Son Stone Company; 1950-01-01 to 1990-10-23; source msha-controller-operator-history
- **controller_controls_operator:** Goodson Hugh → Sunset Stone Company; 1950-01-01 to 1990-10-23; source msha-controller-operator-history
- **operator_operates_mine:** Kemp & Son Stone Company → Kemp & Son Stone Company; 1990-10-24 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Kemp Roy L → Kemp & Son Stone Company; 1990-10-24 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Kemp Roy L → Kemp & Son Stone Company; 1990-10-24 to current/open; source msha-controller-operator-history