# Relationship history for MSHA mine 3101801

Current hierarchy: **Allen Richard R → Concrete Service Company Of Jacksonville → Armstrong Pit**

- 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 R Armstrong & Son Inc → Armstrong Pit; 1950-01-01 to 1978-09-15; source msha-controller-operator-history
- **controller_controls_mine:** Armstrong L R & Son Inc → Armstrong Pit; 1950-01-01 to 1978-09-15; source msha-controller-operator-history
- **controller_controls_operator:** Armstrong L R & Son Inc → L R Armstrong & Son Inc; 1950-01-01 to 1978-09-15; source msha-controller-operator-history
- **operator_operates_mine:** Concrete Service Company Of Jacksonville → Armstrong Pit; 1978-09-16 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Allen Richard R → Armstrong Pit; 1978-09-16 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Allen Richard R → Concrete Service Company Of Jacksonville; 1978-09-16 to current/open; source msha-controller-operator-history