# Relationship history for MSHA mine 4201196

Current hierarchy: **Vern  Shumway → V & S Mining → Mc Cormick Drift**

- 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

- **operator_operates_mine:** Minerals West Inc → Mc Cormick Drift; 1950-01-01 to 1983-08-14; source msha-controller-operator-history
- **controller_controls_mine:** Nielson Stephen M → Mc Cormick Drift; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Nielson Stephen M → Minerals West Inc; 1950-01-01 to 1983-08-14; source msha-controller-operator-history
- **controller_controls_mine:** Rio Algom Ltd → Mc Cormick Drift; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Rio Algom Corp → Mc Cormick Drift; 1983-08-15 to 1986-05-19; source msha-controller-operator-history
- **controller_controls_operator:** Rio Algom Ltd → Rio Algom Corp; 1983-08-15 to 1986-05-19; source msha-controller-operator-history
- **operator_operates_mine:** R & B Mining Inc → Mc Cormick Drift; 1986-05-20 to 1987-12-06; source msha-controller-operator-history
- **controller_controls_mine:** Bill  Nielson et al → Mc Cormick Drift; 1986-05-20 to 1998-07-21; source msha-controller-operator-history
- **controller_controls_operator:** Bill  Nielson et al → R & B Mining Inc; 1986-05-20 to 1987-12-06; source msha-controller-operator-history
- **operator_operates_mine:** V & S Mining → Mc Cormick Drift; 1987-12-07 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Vern  Shumway → Mc Cormick Drift; 1987-12-07 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Vern  Shumway → V & S Mining; 1987-12-07 to current/open; source msha-controller-operator-history