# Relationship history for MSHA mine 1500038

Current hierarchy: **Gibson H Mack & Shirley → Mountain Branch Limestone Company → Gibson 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:** Johnson Brothers Limestone Company → Gibson Quarry; 1950-01-01 to 1981-12-08; source msha-controller-operator-history
- **controller_controls_mine:** Johnson James B & Onsby C → Gibson Quarry; 1950-01-01 to 1981-12-08; source msha-controller-operator-history
- **controller_controls_operator:** Johnson James B & Onsby C → Johnson Brothers Limestone Company; 1950-01-01 to 1981-12-08; source msha-controller-operator-history
- **operator_operates_mine:** Mountain Branch Limestone Company → Gibson Quarry; 1981-12-09 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Gibson H Mack & Shirley → Gibson Quarry; 1981-12-09 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Gibson H Mack & Shirley → Mountain Branch Limestone Company; 1981-12-09 to current/open; source msha-controller-operator-history