# Relationship history for MSHA mine 1900317

Current hierarchy: **Joseph  Montalto → Holden Sand & Gravel Company → Holden Sand & Gravel Company**

- 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:** Holden Sand & Gravel Company → Holden Sand & Gravel Company; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Migdelany Edward G → Holden Sand & Gravel Company; 1950-01-01 to 2002-08-31; source msha-controller-operator-history
- **controller_controls_operator:** Migdelany Edward G → Holden Sand & Gravel Company; 1950-01-01 to 2002-08-31; source msha-controller-operator-history
- **controller_controls_mine:** Joseph  Montalto → Holden Sand & Gravel Company; 2002-09-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Joseph  Montalto → Holden Sand & Gravel Company; 2002-09-01 to current/open; source msha-controller-operator-history