# Relationship history for MSHA mine 4703607

Current hierarchy: **Iron Oak Energy Solutions LLC → Superior Silica Sands, LLC → Chippewa Sand**

- 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:** Fred Weber, Inc. → Chippewa Sand; 1997-11-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Insight Equity et al → Chippewa Sand; 2008-06-21 to 2019-12-09; source msha-controller-operator-history
- **operator_operates_mine:** Iron Mountain Trap Rock → Chippewa Sand; 2011-05-11 to 2019-12-09; source msha-controller-operator-history
- **controller_controls_operator:** Fred Weber, Inc. → Iron Mountain Trap Rock; 2011-05-11 to 2019-12-09; source msha-controller-operator-history
- **operator_operates_mine:** Superior Silica Sands, LLC → Chippewa Sand; 2019-12-10 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Insight Equity et al → Superior Silica Sands, LLC; 2019-12-10 to 2019-12-09; source msha-controller-operator-history
- **controller_controls_mine:** HPS Investment Partners et al → Chippewa Sand; 2019-12-10 to 2025-12-15; source msha-controller-operator-history
- **controller_controls_operator:** HPS Investment Partners et al → Superior Silica Sands, LLC; 2019-12-10 to 2025-12-15; source msha-controller-operator-history
- **controller_controls_operator:** Oak Hill Advisors et al → Superior Silica Sands, LLC; 2019-12-10 to 2025-12-15; source msha-controller-operator-history
- **controller_controls_operator:** PIMCO et al → Superior Silica Sands, LLC; 2019-12-10 to 2025-12-15; source msha-controller-operator-history
- **controller_controls_mine:** Iron Oak Energy Solutions LLC → Chippewa Sand; 2025-12-16 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Iron Oak Energy Solutions LLC → Superior Silica Sands, LLC; 2025-12-16 to current/open; source msha-controller-operator-history