# Relationship history for MSHA mine 2901484

Current hierarchy: **Straughan Bernice → Dolphin Trucking → Dolphin Trucking Pit**

- 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:** South Albuquerque Sand & Gravel Company → Dolphin Trucking Pit; 1950-01-01 to 1980-04-20; source msha-controller-operator-history
- **controller_controls_mine:** Douglas Ron → Dolphin Trucking Pit; 1950-01-01 to 1980-04-20; source msha-controller-operator-history
- **controller_controls_operator:** Douglas Ron → South Albuquerque Sand & Gravel Company; 1950-01-01 to 1980-04-20; source msha-controller-operator-history
- **operator_operates_mine:** Coyote Star Paving → Dolphin Trucking Pit; 1980-04-21 to 1986-06-11; source msha-controller-operator-history
- **controller_controls_mine:** Anthony  Villegas → Dolphin Trucking Pit; 1980-04-21 to 1986-06-11; source msha-controller-operator-history
- **controller_controls_operator:** Anthony  Villegas → Coyote Star Paving; 1980-04-21 to 1986-06-11; source msha-controller-operator-history
- **operator_operates_mine:** Dolphin Trucking → Dolphin Trucking Pit; 1986-06-12 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Straughan Bernice → Dolphin Trucking Pit; 1986-06-12 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Straughan Bernice → Dolphin Trucking; 1986-06-12 to current/open; source msha-controller-operator-history