# Relationship history for MSHA mine 2601661

Current hierarchy: **W S Holding Corp → Western States Minerals Corp → Northumberland**

- 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:** S J Groves & Sons Company → Northumberland; 1978-08-01 to 1990-01-07; source msha-controller-operator-history
- **operator_operates_mine:** Cyprus Northumberland Mining Company → Northumberland; 1980-07-01 to 1985-07-17; source msha-controller-operator-history
- **controller_controls_mine:** Cyprus Amax Minerals Company → Northumberland; 1980-07-01 to 1985-07-17; source msha-controller-operator-history
- **controller_controls_operator:** Cyprus Amax Minerals Company → Cyprus Northumberland Mining Company; 1980-07-01 to 1985-07-17; source msha-controller-operator-history
- **operator_operates_mine:** Western States Minerals Corp → Northumberland; 1985-07-18 to 1990-01-07; source msha-controller-operator-history
- **controller_controls_operator:** S J Groves & Sons Company → Western States Minerals Corp; 1985-07-18 to 1990-01-07; source msha-controller-operator-history
- **controller_controls_mine:** W S Holding Corp → Northumberland; 1989-07-23 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Western States Minerals Corp → Northumberland; 1990-01-08 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** W S Holding Corp → Western States Minerals Corp; 1990-01-08 to current/open; source msha-controller-operator-history