# Relationship history for MSHA mine 3300110

Current hierarchy: **Michael  Carlow → S M E Lime & Chemical Company Inc → Silica Stone 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:** Medusa Cement Company → Silica Stone Quarry; 1950-01-01 to 1978-12-31; source msha-controller-operator-history
- **controller_controls_mine:** Medusa Corp → Silica Stone Quarry; 1950-01-01 to 1978-12-31; source msha-controller-operator-history
- **controller_controls_operator:** Medusa Corp → Medusa Cement Company; 1950-01-01 to 1978-12-31; source msha-controller-operator-history
- **operator_operates_mine:** Medusa Cement Company → Silica Stone Quarry; 1979-01-01 to 1982-09-07; source msha-controller-operator-history
- **controller_controls_mine:** Crane Company → Silica Stone Quarry; 1979-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Crane Company → Medusa Cement Company; 1979-01-01 to 1982-09-07; source msha-controller-operator-history
- **operator_operates_mine:** S M E Lime & Chemical Company Inc → Silica Stone Quarry; 1982-09-08 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Michael  Carlow  et al → Silica Stone Quarry; 1982-09-08 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Michael  Carlow  et al → S M E Lime & Chemical Company Inc; 1982-09-08 to current/open; source msha-controller-operator-history