# Relationship history for MSHA mine 2401911

Current hierarchy: **Stansbury Holdings Corp → International Vermiculite (Montana) Inc → ELK GULCH VERMICULITE 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

- **operator_operates_mine:** Mineral Products Inc → ELK GULCH VERMICULITE MINE; 1990-04-01 to 1996-09-03; source msha-controller-operator-history
- **controller_controls_mine:** Mineral Products Inc → ELK GULCH VERMICULITE MINE; 1990-04-01 to 1996-09-03; source msha-controller-operator-history
- **controller_controls_operator:** Mineral Products Inc → Mineral Products Inc; 1990-04-01 to 1996-09-03; source msha-controller-operator-history
- **operator_operates_mine:** Resource Vermiculite Ltd → ELK GULCH VERMICULITE MINE; 1996-09-04 to 1997-10-09; source msha-controller-operator-history
- **controller_controls_mine:** John J  Tanigawa et al → ELK GULCH VERMICULITE MINE; 1996-09-04 to 1997-10-09; source msha-controller-operator-history
- **controller_controls_operator:** John J  Tanigawa et al → Resource Vermiculite Ltd; 1996-09-04 to 1997-10-09; source msha-controller-operator-history
- **operator_operates_mine:** International Vermiculite (Montana) Inc → ELK GULCH VERMICULITE MINE; 1997-10-10 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Stansbury Holdings Corp → ELK GULCH VERMICULITE MINE; 1997-10-10 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Stansbury Holdings Corp → International Vermiculite (Montana) Inc; 1997-10-10 to current/open; source msha-controller-operator-history