# Relationship history for MSHA mine 1000556

Current hierarchy: **Western Cooperative Fertilizers (Us) & Nu-West Ind → Conda Partnership → Dry Valley Mine**

- 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:** Washington Corps → Dry Valley Mine; 1950-01-01 to 1981-09-30; source msha-controller-operator-history
- **controller_controls_mine:** Washington Group International Inc → Dry Valley Mine; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Washington Group International Inc → Washington Corps; 1950-01-01 to 1981-09-30; source msha-controller-operator-history
- **operator_operates_mine:** Conda Partnership → Dry Valley Mine; 1981-10-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Western Cooperative Fertilizers (Us) & Nu-West Ind → Dry Valley Mine; 1981-10-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Western Cooperative Fertilizers (Us) & Nu-West Ind → Conda Partnership; 1981-10-01 to current/open; source msha-controller-operator-history