# Relationship history for MSHA mine 3501580

Current hierarchy: **Dave  Hanson; Wendell  Lux → Three Way Portable Crushing → Squirrel Pit & Plant**

- 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:** Lloyd M Hill Construction Inc → Squirrel Pit & Plant; 1950-01-01 to 1978-04-20; source msha-controller-operator-history
- **controller_controls_mine:** Hill Lloyd M Inc → Squirrel Pit & Plant; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Hill Lloyd M Inc → Lloyd M Hill Construction Inc; 1950-01-01 to 1978-04-20; source msha-controller-operator-history
- **operator_operates_mine:** Rockline Inc → Squirrel Pit & Plant; 1978-04-21 to 1980-07-16; source msha-controller-operator-history
- **controller_controls_mine:** Linebarger Carl V → Squirrel Pit & Plant; 1978-04-21 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Linebarger Carl V → Rockline Inc; 1978-04-21 to 1980-07-16; source msha-controller-operator-history
- **controller_controls_mine:** Wendell  Lux et al → Squirrel Pit & Plant; 1979-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Three Way Portable Crushing → Squirrel Pit & Plant; 1980-07-17 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Wendell  Lux et al → Three Way Portable Crushing; 1980-07-17 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Dave  Hanson et al → Three Way Portable Crushing; 1980-07-17 to current/open; source msha-controller-operator-history