# Relationship history for MSHA mine 3101894

Current hierarchy: **F Browne Gregg Trust → Comolli Granite Company → Silvertone 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: 2026-10-18T09:31:49.615908+00:00

## Valid-time edges

- **controller_controls_mine:** Louis  Comolli → Silvertone Quarry; 1950-01-01 to 1980-06-19; source msha-controller-operator-history
- **operator_operates_mine:** Comolli Granite Company → Silvertone Quarry; 1979-01-01 to 1979-12-31; source msha-controller-operator-history
- **controller_controls_operator:** Louis  Comolli → Comolli Granite Company; 1979-01-01 to 1979-12-31; source msha-controller-operator-history
- **operator_operates_mine:** Comolli Granite Company → Silvertone Quarry; 1980-01-01 to 1981-01-04; source msha-controller-operator-history
- **controller_controls_mine:** Marshall B  Mercer → Silvertone Quarry; 1980-01-01 to 1981-01-04; source msha-controller-operator-history
- **controller_controls_operator:** Marshall B  Mercer → Comolli Granite Company; 1980-01-01 to 1981-01-04; source msha-controller-operator-history
- **operator_operates_mine:** Comolli Granite Company → Silvertone Quarry; 1981-01-05 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** F Browne Gregg Trust → Silvertone Quarry; 1981-01-05 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** F Browne Gregg Trust → Comolli Granite Company; 1981-01-05 to current/open; source msha-controller-operator-history