# Relationship history for MSHA mine 4300294

Current hierarchy: **Richard  Colton → R J Colton Company Inc → Plymouth Quarry**

- 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:** Sailer Brothers Construction Inc → Plymouth Quarry; 1950-01-01 to 1986-03-31; source msha-controller-operator-history
- **controller_controls_mine:** Sailer Arnold J → Plymouth Quarry; 1950-01-01 to 1986-03-31; source msha-controller-operator-history
- **controller_controls_operator:** Sailer Arnold J → Sailer Brothers Construction Inc; 1950-01-01 to 1986-03-31; source msha-controller-operator-history
- **operator_operates_mine:** Plymouth Stone Inc → Plymouth Quarry; 1986-04-01 to 1989-09-25; source msha-controller-operator-history
- **controller_controls_mine:** John  Swenor → Plymouth Quarry; 1986-04-01 to 1989-09-25; source msha-controller-operator-history
- **controller_controls_operator:** John  Swenor → Plymouth Stone Inc; 1986-04-01 to 1989-09-25; source msha-controller-operator-history
- **controller_controls_mine:** Richard  Colton → Plymouth Quarry; 1987-07-24 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** R J Colton Company Inc → Plymouth Quarry; 1989-09-26 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Richard  Colton → R J Colton Company Inc; 1989-09-26 to current/open; source msha-controller-operator-history