# Relationship history for MSHA mine 0901220

Current hierarchy: **Michael  Baston; William L Hood IV; Bradley C Ruff → Savannah Gray Quarry, LLC → Savannah Gray 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:** Dale T  Willis → Savannah Gray Quarry; 1991-01-29 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Willis Dimension Stone, Inc. → Savannah Gray Quarry; 2012-05-17 to 2020-06-30; source msha-controller-operator-history
- **controller_controls_operator:** Dale T  Willis → Willis Dimension Stone, Inc.; 2012-05-17 to 2020-06-30; source msha-controller-operator-history
- **operator_operates_mine:** Savannah Gray Quarry, LLC → Savannah Gray Quarry; 2020-07-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Bradley C Ruff et al → Savannah Gray Quarry; 2020-07-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Bradley C Ruff et al → Savannah Gray Quarry, LLC; 2020-07-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** William L Hood IV et al → Savannah Gray Quarry, LLC; 2020-07-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Michael  Baston et al → Savannah Gray Quarry, LLC; 2020-07-01 to current/open; source msha-controller-operator-history