# Relationship history for MSHA mine 3400938

Current hierarchy: **International Chemical Company Inc → Inter-Chem Coal Company Inc → Inter-Chem No 3**

- 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:** Petroleum Reserve Corp → Inter-Chem No 3; 1975-03-25 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Carbonex Coal Company → Inter-Chem No 3; 1976-01-21 to 1984-07-22; source msha-controller-operator-history
- **controller_controls_operator:** Petroleum Reserve Corp → Carbonex Coal Company; 1976-01-21 to 1984-07-22; source msha-controller-operator-history
- **operator_operates_mine:** Coal Corp Operating Co Of Amer-Carbonex Coal Div → Inter-Chem No 3; 1984-07-23 to 1988-04-10; source msha-controller-operator-history
- **controller_controls_mine:** Campbell Resources Inc → Inter-Chem No 3; 1984-07-23 to 1988-04-10; source msha-controller-operator-history
- **controller_controls_operator:** Campbell Resources Inc → Coal Corp Operating Co Of Amer-Carbonex Coal Div; 1984-07-23 to 1988-04-10; source msha-controller-operator-history
- **controller_controls_mine:** International Chemical Company Inc → Inter-Chem No 3; 1986-02-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Inter-Chem Coal Company Inc → Inter-Chem No 3; 1988-04-11 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** International Chemical Company Inc → Inter-Chem Coal Company Inc; 1988-04-11 to current/open; source msha-controller-operator-history