# Relationship history for MSHA mine 0900011

Current hierarchy: **Roberson Kenneth E → Georgia Limestone Company Inc → Perry Quarry & 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: 2026-10-17T05:35:58.500035+00:00

## Valid-time edges

- **operator_operates_mine:** Georgia Limestone Company Inc → Perry Quarry & Plant; 1950-01-01 to 1984-09-26; source msha-controller-operator-history
- **controller_controls_mine:** Henrich Thomas → Perry Quarry & Plant; 1950-01-01 to 1984-09-26; source msha-controller-operator-history
- **controller_controls_operator:** Henrich Thomas → Georgia Limestone Company Inc; 1950-01-01 to 1984-09-26; source msha-controller-operator-history
- **operator_operates_mine:** Georgia Limestone Company Inc → Perry Quarry & Plant; 1984-09-27 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Roberson Kenneth E → Perry Quarry & Plant; 1984-09-27 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Roberson Kenneth E → Georgia Limestone Company Inc; 1984-09-27 to current/open; source msha-controller-operator-history