# Relationship history for MSHA mine 3200460

Current hierarchy: **Tony  Schirado → Schirado Excavation → Schirado Mine**

- 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:** Richter Construction Company → Schirado Mine; 1950-01-01 to 1980-11-04; source msha-controller-operator-history
- **controller_controls_mine:** Richter Wayne → Schirado Mine; 1950-01-01 to 1980-11-04; source msha-controller-operator-history
- **controller_controls_operator:** Richter Wayne → Richter Construction Company; 1950-01-01 to 1980-11-04; source msha-controller-operator-history
- **controller_controls_mine:** Portney Doug → Schirado Mine; 1980-10-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Portney Construction → Schirado Mine; 1980-11-05 to 1984-06-24; source msha-controller-operator-history
- **controller_controls_operator:** Portney Doug → Portney Construction; 1980-11-05 to 1984-06-24; source msha-controller-operator-history
- **operator_operates_mine:** Schirado Excavation → Schirado Mine; 1984-06-25 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Tony  Schirado → Schirado Mine; 1984-06-25 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Tony  Schirado → Schirado Excavation; 1984-06-25 to current/open; source msha-controller-operator-history