# Relationship history for MSHA mine 2800970

Current hierarchy: **Gavin  Hummer; Colton  Hummer → Harmony Sand & Gravel Inc → Harmony Sand & Gravel Inc PL #2**

- 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

- **controller_controls_mine:** Richard L  Hummer et al → Harmony Sand & Gravel Inc PL #2; 1981-03-10 to 2025-09-04; source msha-controller-operator-history
- **operator_operates_mine:** Foul Rift Sand & Gravel Inc → Harmony Sand & Gravel Inc PL #2; 1985-02-01 to 1990-02-21; source msha-controller-operator-history
- **controller_controls_mine:** Robert C  Hummer → Harmony Sand & Gravel Inc PL #2; 1985-02-01 to 1990-02-21; source msha-controller-operator-history
- **controller_controls_operator:** Robert C  Hummer → Foul Rift Sand & Gravel Inc; 1985-02-01 to 1990-02-21; source msha-controller-operator-history
- **operator_operates_mine:** Harmony Sand & Gravel Inc → Harmony Sand & Gravel Inc PL #2; 1990-02-22 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Richard L  Hummer et al → Harmony Sand & Gravel Inc; 1990-02-22 to 2025-09-04; source msha-controller-operator-history
- **controller_controls_mine:** Gavin  Hummer et al → Harmony Sand & Gravel Inc PL #2; 2025-09-05 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Gavin  Hummer et al → Harmony Sand & Gravel Inc; 2025-09-05 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Colton  Hummer et al → Harmony Sand & Gravel Inc; 2025-09-05 to current/open; source msha-controller-operator-history