# Relationship history for MSHA mine 1516000

Current hierarchy: **Simpson Herbert Gaston → Marie Enterprises Inc → No 1 Mine**

- 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

- **controller_controls_mine:** Simpson Herbert Gaston → No 1 Mine; 1986-01-22 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Big Oak Coal Company → No 1 Mine; 1987-04-01 to 1988-06-12; source msha-controller-operator-history
- **controller_controls_mine:** Johnson Robert → No 1 Mine; 1987-04-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Johnson Robert → Big Oak Coal Company; 1987-04-01 to 1988-06-12; source msha-controller-operator-history
- **operator_operates_mine:** Marie Enterprises Inc → No 1 Mine; 1988-06-13 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Simpson Herbert Gaston → Marie Enterprises Inc; 1988-06-13 to current/open; source msha-controller-operator-history