# Relationship history for MSHA mine 0504004

Current hierarchy: **Lester  Wark → Wark Trucking Company → BOCK PIT**

- 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

- **controller_controls_mine:** Continental Materials Corp → BOCK PIT; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Castle Concrete Company → BOCK PIT; 1985-07-01 to 1999-04-13; source msha-controller-operator-history
- **controller_controls_operator:** Continental Materials Corp → Castle Concrete Company; 1985-07-01 to 1999-04-13; source msha-controller-operator-history
- **operator_operates_mine:** Wark Trucking Company → BOCK PIT; 1999-04-14 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Lester  Wark → BOCK PIT; 1999-04-14 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Lester  Wark → Wark Trucking Company; 1999-04-14 to current/open; source msha-controller-operator-history