# Relationship history for MSHA mine 4201211

Current hierarchy: **Wolverine Fuels LLC → Fossil Rock Resources, LLC. → Fossil Rock 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

- **operator_operates_mine:** Trail Mountain Coal Company → Fossil Rock Mine; 1975-10-01 to 1978-12-31; source msha-controller-operator-history
- **controller_controls_mine:** John  Bell → Fossil Rock Mine; 1975-10-01 to 1978-12-31; source msha-controller-operator-history
- **controller_controls_operator:** John  Bell → Trail Mountain Coal Company; 1975-10-01 to 1978-12-31; source msha-controller-operator-history
- **operator_operates_mine:** Trail Mountain Coal Company → Fossil Rock Mine; 1979-01-01 to 1981-03-04; source msha-controller-operator-history
- **controller_controls_mine:** Fetterolf Group Inc → Fossil Rock Mine; 1979-01-01 to 1981-03-04; source msha-controller-operator-history
- **controller_controls_operator:** Fetterolf Group Inc → Trail Mountain Coal Company; 1979-01-01 to 1981-03-04; source msha-controller-operator-history
- **controller_controls_mine:** Atlantic Richfield Company → Fossil Rock Mine; 1980-03-05 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Trail Mountain Coal Company → Fossil Rock Mine; 1981-03-05 to 1987-05-18; source msha-controller-operator-history
- **controller_controls_mine:** Natomas Company → Fossil Rock Mine; 1981-03-05 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Natomas Company → Trail Mountain Coal Company; 1981-03-05 to 1987-05-18; source msha-controller-operator-history
- **controller_controls_mine:** MidAmerican Energy Holdings Company → Fossil Rock Mine; 1986-04-28 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Arch Of Utah → Fossil Rock Mine; 1987-05-19 to 1987-09-30; source msha-controller-operator-history
- **controller_controls_mine:** Ashland Inc et al → Fossil Rock Mine; 1987-05-19 to 1987-09-30; source msha-controller-operator-history
- **controller_controls_operator:** Ashland Inc et al → Arch Of Utah; 1987-05-19 to 1987-09-30; source msha-controller-operator-history
- **operator_operates_mine:** Mountain Coal Company → Fossil Rock Mine; 1987-10-01 to 1992-10-04; source msha-controller-operator-history
- **controller_controls_operator:** Atlantic Richfield Company → Mountain Coal Company; 1987-10-01 to 1992-10-04; source msha-controller-operator-history
- **operator_operates_mine:** Energy West Mining Company → Fossil Rock Mine; 1992-10-05 to 2015-06-04; source msha-controller-operator-history
- **controller_controls_operator:** MidAmerican Energy Holdings Company → Energy West Mining Company; 1992-10-05 to 2015-06-04; source msha-controller-operator-history
- **operator_operates_mine:** Fossil Rock Resources, LLC. → Fossil Rock Mine; 2015-06-05 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Wolverine Fuels LLC → Fossil Rock Mine; 2015-06-05 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Wolverine Fuels LLC → Fossil Rock Resources, LLC.; 2015-06-05 to current/open; source msha-controller-operator-history