# Relationship history for MSHA mine 1000168

Current hierarchy: **North Idaho College → North Idaho College → North Idaho College Atlas Mine**

- Valid-time bounds: inclusive, date granularity
- Null end: open-ended in the upstream history row; not independent proof of present control
- Transaction-time observation: 2026-10-18T09:31:49.615908+00:00

## Valid-time edges

- **controller_controls_mine:** Hecla Mining Company → North Idaho College Atlas Mine; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Atlas Mining Company Noranda Exploration → North Idaho College Atlas Mine; 1950-01-01 to 1982-09-14; source msha-controller-operator-history
- **controller_controls_mine:** Atlas Mining Company Noranda Exploration → North Idaho College Atlas Mine; 1950-01-01 to 1982-09-14; source msha-controller-operator-history
- **controller_controls_operator:** Atlas Mining Company Noranda Exploration → Atlas Mining Company Noranda Exploration; 1950-01-01 to 1982-09-14; source msha-controller-operator-history
- **operator_operates_mine:** Hecla Mining Company → North Idaho College Atlas Mine; 1982-09-15 to 1989-01-22; source msha-controller-operator-history
- **controller_controls_operator:** Hecla Mining Company → Hecla Mining Company; 1982-09-15 to 1989-01-22; source msha-controller-operator-history
- **operator_operates_mine:** North Idaho College → North Idaho College Atlas Mine; 1989-01-23 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** North Idaho College → North Idaho College Atlas Mine; 1989-01-23 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** North Idaho College → North Idaho College; 1989-01-23 to current/open; source msha-controller-operator-history