# Relationship history for MSHA mine 2200478

Current hierarchy: **Dunn Investment Company → Hard Rock Sand & Grvl → MMC Materials, Inc.**

- Valid-time bounds: inclusive, date granularity
- Null end: open-ended in the upstream history row; not independent proof of present control
- Transaction-time observation: 2026-10-17T05:35:58.500035+00:00

## Valid-time edges

- **operator_operates_mine:** Oxford Sand Co., Inc → MMC Materials, Inc.; 1979-01-01 to 2021-01-03; source msha-controller-operator-history
- **controller_controls_mine:** Jerry K White → MMC Materials, Inc.; 1979-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Jerry K White → Oxford Sand Co., Inc; 1979-01-01 to 2021-01-03; source msha-controller-operator-history
- **operator_operates_mine:** Hard Rock Sand & Grvl → MMC Materials, Inc.; 2021-01-04 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Eddie  Middleton et al → MMC Materials, Inc.; 2021-01-04 to 2022-05-16; source msha-controller-operator-history
- **controller_controls_operator:** Eddie  Middleton et al → Hard Rock Sand & Grvl; 2021-01-04 to 2022-05-16; source msha-controller-operator-history
- **controller_controls_operator:** Rodney  Grogan et al → Hard Rock Sand & Grvl; 2021-01-04 to 2022-05-16; source msha-controller-operator-history
- **controller_controls_mine:** Dunn Investment Company → MMC Materials, Inc.; 2022-05-17 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Dunn Investment Company → Hard Rock Sand & Grvl; 2022-05-17 to current/open; source msha-controller-operator-history