# Relationship history for MSHA mine 4103942

Current hierarchy: **Simpson Michael & Shelly → M & S Simpson Stone → M & S SIMPSON STONE**

- 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:** M & S Simpson Stone → M & S SIMPSON STONE; 1997-03-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Simpson Michael & Shelly → M & S SIMPSON STONE; 1997-03-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Simpson Michael & Shelly → M & S Simpson Stone; 1997-03-01 to current/open; source msha-controller-operator-history