# Relationship history for MSHA mine 4606875

Current hierarchy: **Graybeal Carl N & Jack L Williams → G & W Equipment Leasing Inc → Tioga Surface 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

- **controller_controls_mine:** Graybeal Carl N & Jack L Williams → Tioga Surface Mine; 1981-12-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** G & W Equipment Leasing Inc → Tioga Surface Mine; 1985-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Graybeal Carl N & Jack L Williams → G & W Equipment Leasing Inc; 1985-01-01 to current/open; source msha-controller-operator-history