# Relationship history for MSHA mine 4700942

Current hierarchy: **Tom  Halquist; Bill  Halquist → Halquist Stone Company Inc → North Lake Pit**

- 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:** Bill  Halquist et al → North Lake Pit; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** North Lake Sand & Gravel → North Lake Pit; 1981-11-01 to 2018-07-10; source msha-controller-operator-history
- **controller_controls_mine:** Halquist Stone Co Inc et al → North Lake Pit; 1981-11-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Halquist Stone Co Inc et al → North Lake Sand & Gravel; 1981-11-01 to 2018-07-10; source msha-controller-operator-history
- **controller_controls_operator:** L & W Construction Co Inc et al → North Lake Sand & Gravel; 1981-11-01 to 2018-07-10; source msha-controller-operator-history
- **operator_operates_mine:** Halquist Stone Company Inc → North Lake Pit; 2018-07-11 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Bill  Halquist et al → Halquist Stone Company Inc; 2018-07-11 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Tom  Halquist et al → Halquist Stone Company Inc; 2018-07-11 to current/open; source msha-controller-operator-history