# Relationship history for MSHA mine 0504477

Current hierarchy: **Camas Plc → C & M Aggregates Ltd → Williams 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

- **operator_operates_mine:** C & M Ready Mix Concrete Company Of Boulder → Williams Pit; 1991-01-01 to 1994-10-27; source msha-controller-operator-history
- **controller_controls_mine:** David B  Nystrom → Williams Pit; 1991-01-01 to 1994-10-27; source msha-controller-operator-history
- **controller_controls_operator:** David B  Nystrom → C & M Ready Mix Concrete Company Of Boulder; 1991-01-01 to 1994-10-27; source msha-controller-operator-history
- **operator_operates_mine:** C & M Aggregates Ltd → Williams Pit; 1994-10-28 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Camas Plc → Williams Pit; 1994-10-28 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Camas Plc → C & M Aggregates Ltd; 1994-10-28 to current/open; source msha-controller-operator-history