# Relationship history for MSHA mine 4406520

Current hierarchy: **Thyssen Schachtbau Gmbh → Parts Corp Of America → #1**

- 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:** Roberts Thomas W Et Al → #1; 1981-06-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Yates Elzie → #1; 1981-12-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Phipps Tom → #1; 1989-03-24 to 1990-01-25; source msha-controller-operator-history
- **operator_operates_mine:** Orex Coal Inc → #1; 1989-06-01 to 1990-01-25; source msha-controller-operator-history
- **controller_controls_operator:** Phipps Tom → Orex Coal Inc; 1989-06-01 to 1990-01-25; source msha-controller-operator-history
- **operator_operates_mine:** Ida Carbon Corp → #1; 1990-01-26 to 1990-07-31; source msha-controller-operator-history
- **controller_controls_operator:** Yates Elzie → Ida Carbon Corp; 1990-01-26 to 1990-07-31; source msha-controller-operator-history
- **operator_operates_mine:** Cavalier Mining Corp → #1; 1990-08-01 to 1991-05-27; source msha-controller-operator-history
- **controller_controls_operator:** Roberts Thomas W Et Al → Cavalier Mining Corp; 1990-08-01 to 1991-05-27; source msha-controller-operator-history
- **operator_operates_mine:** Parts Corp Of America → #1; 1991-05-28 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Thyssen Schachtbau Gmbh → #1; 1991-05-28 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Thyssen Schachtbau Gmbh → Parts Corp Of America; 1991-05-28 to current/open; source msha-controller-operator-history