# Relationship history for MSHA mine 0102047

Current hierarchy: **J Chris  Swift → Becker Sand & Gravel Company Inc → Becker Sand & Gravel Tyler Plant**

- Valid-time bounds: inclusive, date granularity
- Null end: open-ended in the upstream history row; not independent proof of present control
- Transaction-time observation: 2026-10-18T09:31:49.615908+00:00

## Valid-time edges

- **controller_controls_mine:** J Chris  Swift → Becker Sand & Gravel Tyler Plant; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Rachels W H → Becker Sand & Gravel Tyler Plant; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Tyler Sand & Gravel → Becker Sand & Gravel Tyler Plant; 1979-01-01 to 1980-01-07; source msha-controller-operator-history
- **controller_controls_operator:** Rachels W H → Tyler Sand & Gravel; 1979-01-01 to 1980-01-07; source msha-controller-operator-history
- **operator_operates_mine:** Becker Sand & Gravel Company Inc → Becker Sand & Gravel Tyler Plant; 1980-01-08 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** J Chris  Swift → Becker Sand & Gravel Company Inc; 1980-01-08 to current/open; source msha-controller-operator-history