# Relationship history for MSHA mine 1001680

Current hierarchy: **S. D. SANDERS INC; STONEHILL GROUP INC → SANDSTONE MATERIALS, LLC → SANDSTONE MATERIALS, LLC**

- 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:** MJB Materials Co → SANDSTONE MATERIALS, LLC; 1985-06-01 to 2004-12-31; source msha-controller-operator-history
- **controller_controls_mine:** Marland G  Curtis et al → SANDSTONE MATERIALS, LLC; 1985-06-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Marland G  Curtis et al → MJB Materials Co; 1985-06-01 to 2004-12-31; source msha-controller-operator-history
- **controller_controls_operator:** William C  Warmenhoven et al → MJB Materials Co; 1985-06-01 to 2004-12-31; source msha-controller-operator-history
- **operator_operates_mine:** SANDSTONE MATERIALS, LLC → SANDSTONE MATERIALS, LLC; 2005-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** STONEHILL GROUP INC → SANDSTONE MATERIALS, LLC; 2005-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** STONEHILL GROUP INC → SANDSTONE MATERIALS, LLC; 2005-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** S. D. SANDERS INC → SANDSTONE MATERIALS, LLC; 2005-01-01 to current/open; source msha-controller-operator-history