# Relationship history for MSHA mine 1600761

Current hierarchy: **Hazel T  Cowan → J K Cowan Sr Contracting Company Inc → Cowan Dirt Pit #1 & #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: 2026-10-17T05:35:58.500035+00:00

## Valid-time edges

- **operator_operates_mine:** Jones & Lockhart Inc → Cowan Dirt Pit #1 & #2; 1950-01-01 to 1978-06-06; source msha-controller-operator-history
- **controller_controls_mine:** Jones & Lockhart Inc → Cowan Dirt Pit #1 & #2; 1950-01-01 to 1978-06-06; source msha-controller-operator-history
- **controller_controls_operator:** Jones & Lockhart Inc → Jones & Lockhart Inc; 1950-01-01 to 1978-06-06; source msha-controller-operator-history
- **operator_operates_mine:** Johnson Boys Gravel Pit → Cowan Dirt Pit #1 & #2; 1978-06-07 to 1979-10-22; source msha-controller-operator-history
- **controller_controls_mine:** Johnson Max L → Cowan Dirt Pit #1 & #2; 1978-06-07 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Johnson Max L → Johnson Boys Gravel Pit; 1978-06-07 to 1979-10-22; source msha-controller-operator-history
- **controller_controls_mine:** Hazel T  Cowan → Cowan Dirt Pit #1 & #2; 1979-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** J K Cowan Sr Contracting Company Inc → Cowan Dirt Pit #1 & #2; 1979-10-23 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Hazel T  Cowan → J K Cowan Sr Contracting Company Inc; 1979-10-23 to current/open; source msha-controller-operator-history