# Relationship history for MSHA mine 0501780

Current hierarchy: **Mendisco Mark & Marce → Mendisco Mining → September Morn**

- 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:** Union Carbide Corp → September Morn; 1950-01-01 to 1980-03-18; source msha-controller-operator-history
- **controller_controls_mine:** Union Carbide Corp → September Morn; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Union Carbide Corp → Union Carbide Corp; 1950-01-01 to 1980-03-18; source msha-controller-operator-history
- **controller_controls_mine:** Holland Michael R → September Morn; 1979-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Michael R Holland → September Morn; 1980-03-19 to 1980-06-04; source msha-controller-operator-history
- **controller_controls_operator:** Holland Michael R → Michael R Holland; 1980-03-19 to 1980-06-04; source msha-controller-operator-history
- **operator_operates_mine:** Union Carbide Corp → September Morn; 1980-06-05 to 1988-02-07; source msha-controller-operator-history
- **controller_controls_operator:** Union Carbide Corp → Union Carbide Corp; 1980-06-05 to 1988-02-07; source msha-controller-operator-history
- **controller_controls_mine:** Mendisco Mark & Marce → September Morn; 1987-02-12 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Michael R Holland → September Morn; 1988-02-08 to 1990-07-29; source msha-controller-operator-history
- **controller_controls_operator:** Holland Michael R → Michael R Holland; 1988-02-08 to 1990-07-29; source msha-controller-operator-history
- **operator_operates_mine:** Mendisco Mining → September Morn; 1990-07-30 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Mendisco Mark & Marce → Mendisco Mining; 1990-07-30 to current/open; source msha-controller-operator-history