# Relationship history for MSHA mine 2901809

Current hierarchy: **Baca Alfred → Alfred Baca Trucking → BACA 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:** Gallegos Sand & Gravel → BACA PIT; 1980-01-01 to 1981-11-30; source msha-controller-operator-history
- **controller_controls_mine:** Gallegos Henry → BACA PIT; 1980-01-01 to 1981-11-30; source msha-controller-operator-history
- **controller_controls_operator:** Gallegos Henry → Gallegos Sand & Gravel; 1980-01-01 to 1981-11-30; source msha-controller-operator-history
- **operator_operates_mine:** Algodones Sand & Gravel → BACA PIT; 1981-12-01 to 1985-09-23; source msha-controller-operator-history
- **controller_controls_mine:** Chavez Dennis C Et Al → BACA PIT; 1981-12-01 to 1985-09-23; source msha-controller-operator-history
- **controller_controls_operator:** Chavez Dennis C Et Al → Algodones Sand & Gravel; 1981-12-01 to 1985-09-23; source msha-controller-operator-history
- **operator_operates_mine:** Algodones Sand & Gravel → BACA PIT; 1985-09-24 to 1998-11-12; source msha-controller-operator-history
- **controller_controls_mine:** Martinez George Et Al → BACA PIT; 1985-09-24 to 1998-11-12; source msha-controller-operator-history
- **controller_controls_operator:** Martinez George Et Al → Algodones Sand & Gravel; 1985-09-24 to 1998-11-12; source msha-controller-operator-history
- **operator_operates_mine:** Alfred Baca Trucking → BACA PIT; 1998-11-13 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Baca Alfred → BACA PIT; 1998-11-13 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Baca Alfred → Alfred Baca Trucking; 1998-11-13 to current/open; source msha-controller-operator-history