# Relationship history for MSHA mine 2800471

Current hierarchy: **Joseph  Stavola III; Richard J  Stavola → Stavola Sand & Gravel Inc → Stavola Sand & Gravel Incorporated**

- Valid-time bounds: inclusive, date granularity
- Null end: open-ended in the upstream history row; not independent proof of present control
- Transaction-time observation: 2026-10-18T09:31:49.615908+00:00

## Valid-time edges

- **operator_operates_mine:** Houdaille Construction Materials Inc → Stavola Sand & Gravel Incorporated; 1950-01-01 to 1978-03-31; source msha-controller-operator-history
- **controller_controls_mine:** Houdaille Industries Inc → Stavola Sand & Gravel Incorporated; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Houdaille Industries Inc → Houdaille Construction Materials Inc; 1950-01-01 to 1978-03-31; source msha-controller-operator-history
- **operator_operates_mine:** Stavola Sand & Gravel Inc → Stavola Sand & Gravel Incorporated; 1978-04-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Richard J  Stavola et al → Stavola Sand & Gravel Incorporated; 1978-04-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Richard J  Stavola et al → Stavola Sand & Gravel Inc; 1978-04-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Joseph  Stavola III et al → Stavola Sand & Gravel Inc; 1978-04-01 to current/open; source msha-controller-operator-history