# Relationship history for MSHA mine 4403492

Current hierarchy: **Boyd W S & Associates → W S Boyd & Associates → No 1-Strip**

- 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

- **controller_controls_mine:** Turner J M Company Inc → No 1-Strip; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** J M Turner Co Inc → No 1-Strip; 1973-01-01 to 1974-05-31; source msha-controller-operator-history
- **controller_controls_operator:** Turner J M Company Inc → J M Turner Co Inc; 1973-01-01 to 1974-05-31; source msha-controller-operator-history
- **operator_operates_mine:** W S Boyd & Associates → No 1-Strip; 1974-06-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Boyd W S & Associates → No 1-Strip; 1974-06-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Boyd W S & Associates → W S Boyd & Associates; 1974-06-01 to current/open; source msha-controller-operator-history