# Relationship history for MSHA mine 2401753

Current hierarchy: **Costain Group Plc → Montana Talc Company → Johnny Gulch 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: 2026-10-17T05:35:58.500035+00:00

## Valid-time edges

- **controller_controls_mine:** Nicor Minerals Inc → Johnny Gulch Mine; 1982-11-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Nicor Mineral Ventures Inc → Johnny Gulch Mine; 1984-01-01 to 1985-12-03; source msha-controller-operator-history
- **controller_controls_operator:** Nicor Minerals Inc → Nicor Mineral Ventures Inc; 1984-01-01 to 1985-12-03; source msha-controller-operator-history
- **operator_operates_mine:** Montana Talc Company → Johnny Gulch Mine; 1985-12-04 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Costain Group Plc → Johnny Gulch Mine; 1985-12-04 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Costain Group Plc → Montana Talc Company; 1985-12-04 to current/open; source msha-controller-operator-history