# Relationship history for MSHA mine 4201614

Current hierarchy: **Ryan Richard L → Ryan Drilling → Cactus Rat Mine #1**

- 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:** B & L Mining → Cactus Rat Mine #1; 1979-01-01 to 1980-03-17; source msha-controller-operator-history
- **controller_controls_mine:** Lear Bill → Cactus Rat Mine #1; 1979-01-01 to 1980-03-17; source msha-controller-operator-history
- **controller_controls_operator:** Lear Bill → B & L Mining; 1979-01-01 to 1980-03-17; source msha-controller-operator-history
- **operator_operates_mine:** Ryan Drilling → Cactus Rat Mine #1; 1980-03-18 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Ryan Richard L → Cactus Rat Mine #1; 1980-03-18 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Ryan Richard L → Ryan Drilling; 1980-03-18 to current/open; source msha-controller-operator-history