# Relationship history for MSHA mine 4606468

Current hierarchy: **Watts Kyle → Tug Valley Dredge → Tug Valley Dredge**

- 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:** Valley Sand & Gravel Company Inc → Tug Valley Dredge; 1981-12-01 to 1987-03-10; source msha-controller-operator-history
- **controller_controls_mine:** Neilson Alfred → Tug Valley Dredge; 1981-12-01 to 1987-03-10; source msha-controller-operator-history
- **controller_controls_operator:** Neilson Alfred → Valley Sand & Gravel Company Inc; 1981-12-01 to 1987-03-10; source msha-controller-operator-history
- **operator_operates_mine:** Tug Valley Dredge → Tug Valley Dredge; 1987-03-11 to 1988-09-27; source msha-controller-operator-history
- **controller_controls_mine:** Cook Dave → Tug Valley Dredge; 1987-03-11 to 1988-09-27; source msha-controller-operator-history
- **controller_controls_operator:** Cook Dave → Tug Valley Dredge; 1987-03-11 to 1988-09-27; source msha-controller-operator-history
- **operator_operates_mine:** Tug Valley Dredge → Tug Valley Dredge; 1988-09-28 to 1993-08-12; source msha-controller-operator-history
- **controller_controls_mine:** Lyalls James A → Tug Valley Dredge; 1988-09-28 to 1993-08-12; source msha-controller-operator-history
- **controller_controls_operator:** Lyalls James A → Tug Valley Dredge; 1988-09-28 to 1993-08-12; source msha-controller-operator-history
- **operator_operates_mine:** Tug Valley Dredge → Tug Valley Dredge; 1993-08-13 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Watts Kyle → Tug Valley Dredge; 1993-08-13 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Watts Kyle → Tug Valley Dredge; 1993-08-13 to current/open; source msha-controller-operator-history