# Relationship history for MSHA mine 3609494

Current hierarchy: **Joseph  Zimring → Rolling Rock Building Stone, Inc. → Stonemont Mine**

- 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

- **controller_controls_mine:** Gary L  Weller et al → Stonemont Mine; 1993-12-01 to 2020-07-30; source msha-controller-operator-history
- **operator_operates_mine:** Rolling Rock Building Stone, Inc. → Stonemont Mine; 2007-01-29 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Gary L  Weller et al → Rolling Rock Building Stone, Inc.; 2007-01-29 to 2020-07-30; source msha-controller-operator-history
- **controller_controls_mine:** Joseph  Zimring → Stonemont Mine; 2020-07-31 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Joseph  Zimring → Rolling Rock Building Stone, Inc.; 2020-07-31 to current/open; source msha-controller-operator-history