# Relationship history for MSHA mine 0600200

Current hierarchy: **Douglas H  Anderson → Tony Calabro Sons Inc → PEARL LAKE ROAD PIT & MILL**

- 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:** Tony Calabro Sons Inc → PEARL LAKE ROAD PIT & MILL; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Francis  Calabro → PEARL LAKE ROAD PIT & MILL; 1950-01-01 to 2026-03-16; source msha-controller-operator-history
- **controller_controls_operator:** Francis  Calabro → Tony Calabro Sons Inc; 1950-01-01 to 2026-03-16; source msha-controller-operator-history
- **controller_controls_mine:** Douglas H  Anderson → PEARL LAKE ROAD PIT & MILL; 2026-03-17 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Douglas H  Anderson → Tony Calabro Sons Inc; 2026-03-17 to current/open; source msha-controller-operator-history