# Relationship history for MSHA mine 2102707

Current hierarchy: **Jeffrey L  Folland; Don I  Peterson → Halma Sand & Gravel → Halma Sand & Gravel**

- 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:** Garry Gravel → Halma Sand & Gravel; 1979-01-01 to 1990-06-18; source msha-controller-operator-history
- **controller_controls_mine:** Dorothy L  Garry → Halma Sand & Gravel; 1979-01-01 to 1990-06-18; source msha-controller-operator-history
- **controller_controls_operator:** Dorothy L  Garry → Garry Gravel; 1979-01-01 to 1990-06-18; source msha-controller-operator-history
- **operator_operates_mine:** Halma Sand & Gravel → Halma Sand & Gravel; 1990-06-19 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Jeffrey L  Folland et al → Halma Sand & Gravel; 1990-06-19 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Jeffrey L  Folland et al → Halma Sand & Gravel; 1990-06-19 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Don I  Peterson et al → Halma Sand & Gravel; 1990-06-19 to current/open; source msha-controller-operator-history