# Relationship history for MSHA mine 3607480

Current hierarchy: **Richard E  Pierson → Richard E. Pierson Materials Corp. → MIDDLEPORT MATERIALS INC.**

- Valid-time bounds: inclusive, date granularity
- Null end: open-ended in the upstream history row; not independent proof of present control
- Transaction-time observation: 2026-10-17T05:35:58.500035+00:00

## Valid-time edges

- **operator_operates_mine:** Middleport Materials Inc → MIDDLEPORT MATERIALS INC.; 1983-07-01 to 1993-09-28; source msha-controller-operator-history
- **controller_controls_mine:** Joseph  Walacavage → MIDDLEPORT MATERIALS INC.; 1983-07-01 to 1993-09-28; source msha-controller-operator-history
- **controller_controls_operator:** Joseph  Walacavage → Middleport Materials Inc; 1983-07-01 to 1993-09-28; source msha-controller-operator-history
- **controller_controls_mine:** Richard E  Pierson → MIDDLEPORT MATERIALS INC.; 1990-02-08 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Middleport Materials, Inc. → MIDDLEPORT MATERIALS INC.; 1993-09-29 to 2009-12-07; source msha-controller-operator-history
- **controller_controls_mine:** Brian L  Carpenter → MIDDLEPORT MATERIALS INC.; 1993-09-29 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Brian L  Carpenter → Middleport Materials, Inc.; 1993-09-29 to 2009-12-07; source msha-controller-operator-history
- **operator_operates_mine:** Richard E. Pierson Construction Co., Inc. → MIDDLEPORT MATERIALS INC.; 2009-12-08 to 2014-06-30; source msha-controller-operator-history
- **controller_controls_mine:** Richard E  Pierson → MIDDLEPORT MATERIALS INC.; 2009-12-08 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Richard E  Pierson → Richard E. Pierson Construction Co., Inc.; 2009-12-08 to 2014-06-30; source msha-controller-operator-history
- **operator_operates_mine:** Richard E. Pierson Materials Corp. → MIDDLEPORT MATERIALS INC.; 2014-07-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Richard E  Pierson → Richard E. Pierson Materials Corp.; 2014-07-01 to current/open; source msha-controller-operator-history