# Relationship history for MSHA mine 3002295

Current hierarchy: **Ronald A  Roberts → Roberts Slate Company Inc → Penryhn Hill 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

- **controller_controls_mine:** Ronald A  Roberts → Penryhn Hill Quarry; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Roberts Slate Company Inc → Penryhn Hill Quarry; 1978-03-09 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Ronald A  Roberts → Roberts Slate Company Inc; 1978-03-09 to current/open; source msha-controller-operator-history