# Relationship history for MSHA mine 1512983

Current hierarchy: **Green Holdings Inc → Green Engineering & Mining Company Inc → Gemco No 2**

- 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:** Roy R  Crawford et al → Gemco No 2; 1977-03-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Tango Coal Company Inc → Gemco No 2; 1981-07-01 to 1984-03-28; source msha-controller-operator-history
- **controller_controls_operator:** Roy R  Crawford et al → Tango Coal Company Inc; 1981-07-01 to 1984-03-28; source msha-controller-operator-history
- **controller_controls_mine:** Green Holdings Inc → Gemco No 2; 1983-12-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Green Engineering & Mining Company Inc → Gemco No 2; 1984-03-29 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Green Holdings Inc → Green Engineering & Mining Company Inc; 1984-03-29 to current/open; source msha-controller-operator-history