# Relationship history for MSHA mine 3500962

Current hierarchy: **R Gary  Ferguson → Ferguson Logging Company → L & T Quarry**

- 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:** L & T Crushing Company → L & T Quarry; 1978-03-09 to 1980-03-31; source msha-controller-operator-history
- **controller_controls_mine:** Andrew  Lalack → L & T Quarry; 1978-03-09 to 1980-03-31; source msha-controller-operator-history
- **controller_controls_operator:** Andrew  Lalack → L & T Crushing Company; 1978-03-09 to 1980-03-31; source msha-controller-operator-history
- **operator_operates_mine:** Morse Brothers L & T Crushing → L & T Quarry; 1980-04-01 to 1985-07-31; source msha-controller-operator-history
- **controller_controls_mine:** Morse Brothers Inc → L & T Quarry; 1980-04-01 to 1985-07-31; source msha-controller-operator-history
- **controller_controls_operator:** Morse Brothers Inc → Morse Brothers L & T Crushing; 1980-04-01 to 1985-07-31; source msha-controller-operator-history
- **controller_controls_mine:** R Gary  Ferguson → L & T Quarry; 1985-02-04 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Ferguson Logging Company → L & T Quarry; 1985-08-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** R Gary  Ferguson → Ferguson Logging Company; 1985-08-01 to current/open; source msha-controller-operator-history