# Relationship history for MSHA mine 4604589

Current hierarchy: **Occidental Petroleum Corp → Island Creek Coal Company → Ritter-Green #1 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

- **controller_controls_mine:** Occidental Petroleum Corp → Ritter-Green #1 Mine; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Sears Casey & Emery Smallman → Ritter-Green #1 Mine; 1973-12-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Taner Coal Company Inc → Ritter-Green #1 Mine; 1975-01-01 to 1976-01-31; source msha-controller-operator-history
- **controller_controls_operator:** Sears Casey & Emery Smallman → Taner Coal Company Inc; 1975-01-01 to 1976-01-31; source msha-controller-operator-history
- **operator_operates_mine:** R W Taylor Coal Inc → Ritter-Green #1 Mine; 1976-02-01 to 1978-03-22; source msha-controller-operator-history
- **controller_controls_mine:** Bryant William S → Ritter-Green #1 Mine; 1976-02-01 to 1978-03-22; source msha-controller-operator-history
- **controller_controls_operator:** Bryant William S → R W Taylor Coal Inc; 1976-02-01 to 1978-03-22; source msha-controller-operator-history
- **operator_operates_mine:** R W Taylor Coal Company Inc → Ritter-Green #1 Mine; 1978-03-23 to 1981-09-24; source msha-controller-operator-history
- **controller_controls_mine:** Carol Coal Company → Ritter-Green #1 Mine; 1978-03-23 to 1981-09-24; source msha-controller-operator-history
- **controller_controls_operator:** Carol Coal Company → R W Taylor Coal Company Inc; 1978-03-23 to 1981-09-24; source msha-controller-operator-history
- **operator_operates_mine:** Ritter-Greene Coal Inc → Ritter-Green #1 Mine; 1981-09-25 to 1984-08-14; source msha-controller-operator-history
- **controller_controls_mine:** Ritter Gary L & William Greene → Ritter-Green #1 Mine; 1981-09-25 to 1984-08-14; source msha-controller-operator-history
- **controller_controls_operator:** Ritter Gary L & William Greene → Ritter-Greene Coal Inc; 1981-09-25 to 1984-08-14; source msha-controller-operator-history
- **operator_operates_mine:** Barnett Supply Company Inc → Ritter-Green #1 Mine; 1984-08-15 to 1986-05-19; source msha-controller-operator-history
- **controller_controls_mine:** Barnett Gloria → Ritter-Green #1 Mine; 1984-08-15 to 1986-05-19; source msha-controller-operator-history
- **controller_controls_operator:** Barnett Gloria → Barnett Supply Company Inc; 1984-08-15 to 1986-05-19; source msha-controller-operator-history
- **operator_operates_mine:** Prescott Mining Company → Ritter-Green #1 Mine; 1986-05-20 to 1987-04-30; source msha-controller-operator-history
- **controller_controls_mine:** Falk Don → Ritter-Green #1 Mine; 1986-05-20 to 1987-04-30; source msha-controller-operator-history
- **controller_controls_operator:** Falk Don → Prescott Mining Company; 1986-05-20 to 1987-04-30; source msha-controller-operator-history
- **operator_operates_mine:** Island Creek Coal Company → Ritter-Green #1 Mine; 1987-05-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Occidental Petroleum Corp → Island Creek Coal Company; 1987-05-01 to current/open; source msha-controller-operator-history