# Relationship history for MSHA mine 2200480

Current hierarchy: **Christopher E  McDonald; Prentis M  McDonald → Blackwell Sand & Gravel LLC → Blackwell Sand & Gravel**

- 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:** Blackwell Sand Company → Blackwell Sand & Gravel; 1979-01-01 to 1981-03-31; source msha-controller-operator-history
- **controller_controls_mine:** Harry  Cooper → Blackwell Sand & Gravel; 1979-01-01 to 1981-03-31; source msha-controller-operator-history
- **controller_controls_operator:** Harry  Cooper → Blackwell Sand Company; 1979-01-01 to 1981-03-31; source msha-controller-operator-history
- **operator_operates_mine:** Blackwell Sand Company, Inc. → Blackwell Sand & Gravel; 1981-04-01 to 2013-09-16; source msha-controller-operator-history
- **controller_controls_mine:** Lamar A  Gidden Jr → Blackwell Sand & Gravel; 1981-04-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Lamar A  Gidden Jr → Blackwell Sand Company, Inc.; 1981-04-01 to 2013-09-16; source msha-controller-operator-history
- **operator_operates_mine:** Blackwell Sand & Gravel LLC → Blackwell Sand & Gravel; 2013-09-17 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Prentis M  McDonald et al → Blackwell Sand & Gravel; 2013-09-17 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Prentis M  McDonald et al → Blackwell Sand & Gravel LLC; 2013-09-17 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Christopher E  McDonald et al → Blackwell Sand & Gravel LLC; 2013-09-17 to current/open; source msha-controller-operator-history