# Relationship history for MSHA mine 2800980

Current hierarchy: **Richard E  Pierson → R E Pierson Materials Corp → Bridgeport Plant**

- 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:** Bridgeport Materials Inc → Bridgeport Plant; 1986-08-01 to 1990-02-07; source msha-controller-operator-history
- **controller_controls_mine:** James B  Speers Jr → Bridgeport Plant; 1986-08-01 to 1990-02-07; source msha-controller-operator-history
- **controller_controls_operator:** James B  Speers Jr → Bridgeport Materials Inc; 1986-08-01 to 1990-02-07; source msha-controller-operator-history
- **operator_operates_mine:** R E Pierson Materials Corp → Bridgeport Plant; 1990-02-08 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Richard E  Pierson → Bridgeport Plant; 1990-02-08 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Richard E  Pierson → R E Pierson Materials Corp; 1990-02-08 to current/open; source msha-controller-operator-history