# Relationship history for MSHA mine 3607988

Current hierarchy: **Hammel Joseph S → Supreme Fuels Inc → Jonrobin Coal**

- 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:** Jonrobin Coal Company → Jonrobin Coal; 1988-01-01 to 1990-04-29; source msha-controller-operator-history
- **controller_controls_mine:** Gathagan John → Jonrobin Coal; 1988-01-01 to 1990-04-29; source msha-controller-operator-history
- **controller_controls_operator:** Gathagan John → Jonrobin Coal Company; 1988-01-01 to 1990-04-29; source msha-controller-operator-history
- **controller_controls_mine:** Hammel Joseph S → Jonrobin Coal; 1990-03-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Supreme Fuels Inc → Jonrobin Coal; 1990-04-30 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Hammel Joseph S → Supreme Fuels Inc; 1990-04-30 to current/open; source msha-controller-operator-history