# Relationship history for MSHA mine 4200100

Current hierarchy: **ACNR Holdings, Inc → Utah American Energy Inc → Horse Canyon 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: 2026-10-13T11:19:05.459773+00:00

## Valid-time edges

- **controller_controls_mine:** Kaiser Steel Corp → Horse Canyon Mine; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** United States Steel Mining Company Inc → Horse Canyon Mine; 1950-01-01 to 1984-12-10; source msha-controller-operator-history
- **controller_controls_mine:** Usx Corp → Horse Canyon Mine; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Usx Corp → United States Steel Mining Company Inc; 1950-01-01 to 1984-12-10; source msha-controller-operator-history
- **operator_operates_mine:** Kaiser Coal Corp → Horse Canyon Mine; 1984-12-11 to 1992-08-23; source msha-controller-operator-history
- **controller_controls_operator:** Kaiser Steel Corp → Kaiser Coal Corp; 1984-12-11 to 1992-08-23; source msha-controller-operator-history
- **operator_operates_mine:** Bxg Inc → Horse Canyon Mine; 1992-08-24 to 1994-05-31; source msha-controller-operator-history
- **controller_controls_mine:** Corman David B → Horse Canyon Mine; 1992-08-24 to 1994-05-31; source msha-controller-operator-history
- **controller_controls_operator:** Corman David B → Bxg Inc; 1992-08-24 to 1994-05-31; source msha-controller-operator-history
- **operator_operates_mine:** Intermountain Power Agency → Horse Canyon Mine; 1994-06-01 to 2000-08-01; source msha-controller-operator-history
- **controller_controls_mine:** Intermountain Power Agency → Horse Canyon Mine; 1994-06-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Intermountain Power Agency → Intermountain Power Agency; 1994-06-01 to 2000-08-01; source msha-controller-operator-history
- **controller_controls_mine:** Robert E  Murray → Horse Canyon Mine; 1999-02-24 to 2020-09-16; source msha-controller-operator-history
- **operator_operates_mine:** Utah American Energy Inc → Horse Canyon Mine; 2000-08-02 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Robert E  Murray → Utah American Energy Inc; 2000-08-02 to 2020-09-16; source msha-controller-operator-history
- **controller_controls_mine:** ACNR Holdings, Inc → Horse Canyon Mine; 2020-09-17 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** ACNR Holdings, Inc → Utah American Energy Inc; 2020-09-17 to current/open; source msha-controller-operator-history