# Relationship history for MSHA mine 2401901

Current hierarchy: **Robert  Powell → Sapphire Pre Mix Inc → SAPPHIRE PRE MIX**

- 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:** Massa Home Center → SAPPHIRE PRE MIX; 1989-08-01 to 1996-01-22; source msha-controller-operator-history
- **controller_controls_mine:** Michael D  Massa → SAPPHIRE PRE MIX; 1989-08-01 to 1996-01-22; source msha-controller-operator-history
- **controller_controls_operator:** Michael D  Massa → Massa Home Center; 1989-08-01 to 1996-01-22; source msha-controller-operator-history
- **operator_operates_mine:** Sapphire Pre Mix Inc → SAPPHIRE PRE MIX; 1996-01-23 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Robert  Powell → SAPPHIRE PRE MIX; 1996-01-23 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Robert  Powell → Sapphire Pre Mix Inc; 1996-01-23 to current/open; source msha-controller-operator-history