# Relationship history for MSHA mine 3304057

Current hierarchy: **K E  Lawton → C B Holms Inc → David Coal (Strip Job) Vein #7**

- 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:** C B Holms Inc → David Coal (Strip Job) Vein #7; 1986-05-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** K E  Lawton → David Coal (Strip Job) Vein #7; 1986-05-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** K E  Lawton → C B Holms Inc; 1986-05-01 to current/open; source msha-controller-operator-history