# Relationship history for MSHA mine 4502854

Current hierarchy: **Walt  Miles → Port Orchard Sand & Gravel Company Inc → Airport Pit**

- 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:** Walt  Miles et al → Airport Pit; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** William F  Cusick → Airport Pit; 1980-04-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Port Orchard Sand & Gravel Company Inc → Airport Pit; 1980-08-01 to 1986-01-29; source msha-controller-operator-history
- **controller_controls_operator:** William F  Cusick → Port Orchard Sand & Gravel Company Inc; 1980-08-01 to 1986-01-29; source msha-controller-operator-history
- **operator_operates_mine:** Port Orchard Sand & Gravel Company Inc → Airport Pit; 1986-01-30 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Walt  Miles et al → Port Orchard Sand & Gravel Company Inc; 1986-01-30 to current/open; source msha-controller-operator-history