# Relationship history for MSHA mine 0503435

Current hierarchy: **State Of Colorado → Colorado Department Of Highways → J Y Johnson**

- 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:** State Of Colorado → J Y Johnson; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Estate of Henry T. Southway Jr. → J Y Johnson; 1978-03-09 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Colorado Department Of Highways → J Y Johnson; 1979-01-01 to 1980-07-23; source msha-controller-operator-history
- **controller_controls_operator:** State Of Colorado → Colorado Department Of Highways; 1979-01-01 to 1980-07-23; source msha-controller-operator-history
- **operator_operates_mine:** Southway Const Co Inc & Asphalt Gravel Prod Inc → J Y Johnson; 1980-07-24 to 1988-01-11; source msha-controller-operator-history
- **controller_controls_operator:** Estate of Henry T. Southway Jr. → Southway Const Co Inc & Asphalt Gravel Prod Inc; 1980-07-24 to 1988-01-11; source msha-controller-operator-history
- **operator_operates_mine:** Colorado Department Of Highways → J Y Johnson; 1988-01-12 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** State Of Colorado → Colorado Department Of Highways; 1988-01-12 to current/open; source msha-controller-operator-history