# Relationship history for MSHA mine 4200150

Current hierarchy: **Rothwell Hank → United Park City Mines Company → Ontario 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:** Noranda Inc → Ontario Mine; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Park City Ventures → Ontario Mine; 1950-01-01 to 1979-07-31; source msha-controller-operator-history
- **controller_controls_mine:** Anaconda Company & Asarco Inc → Ontario Mine; 1950-01-01 to 1979-07-31; source msha-controller-operator-history
- **controller_controls_operator:** Anaconda Company & Asarco Inc → Park City Ventures; 1950-01-01 to 1979-07-31; source msha-controller-operator-history
- **operator_operates_mine:** Noranda Mining Inc → Ontario Mine; 1979-08-01 to 1982-04-14; source msha-controller-operator-history
- **controller_controls_operator:** Noranda Inc → Noranda Mining Inc; 1979-08-01 to 1982-04-14; source msha-controller-operator-history
- **operator_operates_mine:** United Park City Mines Company → Ontario Mine; 1982-04-15 to 1985-08-07; source msha-controller-operator-history
- **controller_controls_mine:** Sears Wheeler M → Ontario Mine; 1982-04-15 to 1985-08-07; source msha-controller-operator-history
- **controller_controls_operator:** Sears Wheeler M → United Park City Mines Company; 1982-04-15 to 1985-08-07; source msha-controller-operator-history
- **operator_operates_mine:** United Park City Mines Company → Ontario Mine; 1985-08-08 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Rothwell Hank → Ontario Mine; 1985-08-08 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Rothwell Hank → United Park City Mines Company; 1985-08-08 to current/open; source msha-controller-operator-history