# Relationship history for MSHA mine 0900858

Current hierarchy: **Marshall B  Mercer → Galaxy Granite Company → Galaxy Blue 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: 2026-10-17T05:35:58.500035+00:00

## Valid-time edges

- **operator_operates_mine:** Galaxy Granite Company → Galaxy Blue Quarry; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Marshall B  Mercer → Galaxy Blue Quarry; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Marshall B  Mercer → Galaxy Granite Company; 1950-01-01 to current/open; source msha-controller-operator-history