# Relationship history for MSHA mine 3608042

Current hierarchy: **Pacific Gas & Electric Co (Pg & E) & Bechtel → U S Operating Services Company → Alden Stripping Operation #2**

- 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:** Vincent  Kassa → Alden Stripping Operation #2; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Silverbrook Anthracite Inc → Alden Stripping Operation #2; 1988-09-01 to 1994-07-17; source msha-controller-operator-history
- **controller_controls_operator:** Vincent  Kassa → Silverbrook Anthracite Inc; 1988-09-01 to 1994-07-17; source msha-controller-operator-history
- **operator_operates_mine:** U S Operating Services Company → Alden Stripping Operation #2; 1994-07-18 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Pacific Gas & Electric Co (Pg & E) & Bechtel → Alden Stripping Operation #2; 1994-07-18 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Pacific Gas & Electric Co (Pg & E) & Bechtel → U S Operating Services Company; 1994-07-18 to current/open; source msha-controller-operator-history