# Relationship history for MSHA mine 1300687

Current hierarchy: **Bill  Boyer → Boyer Ready Mix Sand & Rock Inc → Boyer Pit & 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: 2026-10-13T11:19:05.459773+00:00

## Valid-time edges

- **operator_operates_mine:** Harkness Gravel & Redi-Mix Inc → Boyer Pit & Plant; 1950-01-01 to 1987-05-31; source msha-controller-operator-history
- **controller_controls_mine:** Harkness Alvin → Boyer Pit & Plant; 1950-01-01 to 1987-05-31; source msha-controller-operator-history
- **controller_controls_operator:** Harkness Alvin → Harkness Gravel & Redi-Mix Inc; 1950-01-01 to 1987-05-31; source msha-controller-operator-history
- **operator_operates_mine:** Boyer Ready Mix Sand & Rock Inc → Boyer Pit & Plant; 1987-06-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Bill  Boyer → Boyer Pit & Plant; 1987-06-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Bill  Boyer → Boyer Ready Mix Sand & Rock Inc; 1987-06-01 to current/open; source msha-controller-operator-history