# Relationship history for MSHA mine 0101983

Current hierarchy: **Dean D  Alford → Smith Sand Company → Smith Sand Company Inc**

- 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:** Smith Sand & Gravel Company → Smith Sand Company Inc; 1978-03-09 to 1995-02-28; source msha-controller-operator-history
- **controller_controls_mine:** Keele M  Smith → Smith Sand Company Inc; 1978-03-09 to 1995-02-28; source msha-controller-operator-history
- **controller_controls_operator:** Keele M  Smith → Smith Sand & Gravel Company; 1978-03-09 to 1995-02-28; source msha-controller-operator-history
- **operator_operates_mine:** Smith Sand Inc → Smith Sand Company Inc; 1995-03-01 to 2010-08-19; source msha-controller-operator-history
- **controller_controls_mine:** Donald C  Byrd → Smith Sand Company Inc; 1995-03-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Donald C  Byrd → Smith Sand Inc; 1995-03-01 to 2010-08-19; source msha-controller-operator-history
- **operator_operates_mine:** Smith Sand Company → Smith Sand Company Inc; 2010-08-20 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Dean D  Alford → Smith Sand Company Inc; 2010-08-20 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Dean D  Alford → Smith Sand Company; 2010-08-20 to current/open; source msha-controller-operator-history