# Relationship history for MSHA mine 2200340

Current hierarchy: **Tripp Millard → Millard Tripp Construction Inc → Millard Tripp Construction Incorporated**

- 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:** Brooks Gravel Company → Millard Tripp Construction Incorporated; 1950-01-01 to 1979-07-31; source msha-controller-operator-history
- **controller_controls_mine:** Brooks Gravel Company → Millard Tripp Construction Incorporated; 1950-01-01 to 1979-07-31; source msha-controller-operator-history
- **controller_controls_operator:** Brooks Gravel Company → Brooks Gravel Company; 1950-01-01 to 1979-07-31; source msha-controller-operator-history
- **operator_operates_mine:** Millard Tripp Construction Inc → Millard Tripp Construction Incorporated; 1979-08-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Tripp Millard → Millard Tripp Construction Incorporated; 1979-08-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Tripp Millard → Millard Tripp Construction Inc; 1979-08-01 to current/open; source msha-controller-operator-history