# Relationship history for MSHA mine 4701546

Current hierarchy: **Robert G  Tews; William L  Tews → Tews Company → Burlington Pit (Yard 12)**

- 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:** Conserco Sand & Gravel Inc → Burlington Pit (Yard 12); 1950-01-01 to 1980-01-31; source msha-controller-operator-history
- **controller_controls_mine:** Kron Lester Jr → Burlington Pit (Yard 12); 1950-01-01 to 1980-01-31; source msha-controller-operator-history
- **controller_controls_operator:** Kron Lester Jr → Conserco Sand & Gravel Inc; 1950-01-01 to 1980-01-31; source msha-controller-operator-history
- **controller_controls_mine:** Robert G  Tews et al → Burlington Pit (Yard 12); 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Tews Company → Burlington Pit (Yard 12); 1980-02-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Robert G  Tews et al → Tews Company; 1980-02-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** William L  Tews et al → Tews Company; 1980-02-01 to current/open; source msha-controller-operator-history