# Relationship history for MSHA mine 2700083

Current hierarchy: **Polycor Inc → Swenson Granite Company LLC → SWENSON GRAY QUARRY**

- 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:** Swenson Granite Company LLC → SWENSON GRAY QUARRY; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Robert  Pope → SWENSON GRAY QUARRY; 1950-01-01 to 2016-09-20; source msha-controller-operator-history
- **controller_controls_operator:** Robert  Pope → Swenson Granite Company LLC; 1950-01-01 to 2016-09-20; source msha-controller-operator-history
- **controller_controls_mine:** Polycor Inc → SWENSON GRAY QUARRY; 2016-09-21 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Polycor Inc → Swenson Granite Company LLC; 2016-09-21 to current/open; source msha-controller-operator-history