# Relationship history for MSHA mine 4606036

Current hierarchy: **L Nicholas  Stevens → Salt Lick Coal Corp → Spruce Fork Mine No 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

- **operator_operates_mine:** Helmick & Nutter Inc → Spruce Fork Mine No 1; 1979-07-01 to 1981-03-01; source msha-controller-operator-history
- **controller_controls_mine:** Nutter Jack → Spruce Fork Mine No 1; 1979-07-01 to 1981-03-01; source msha-controller-operator-history
- **controller_controls_operator:** Nutter Jack → Helmick & Nutter Inc; 1979-07-01 to 1981-03-01; source msha-controller-operator-history
- **operator_operates_mine:** Salt Lick Coal Corp → Spruce Fork Mine No 1; 1981-03-02 to 1983-12-07; source msha-controller-operator-history
- **controller_controls_mine:** Brown Chuck → Spruce Fork Mine No 1; 1981-03-02 to 1983-12-07; source msha-controller-operator-history
- **controller_controls_operator:** Brown Chuck → Salt Lick Coal Corp; 1981-03-02 to 1983-12-07; source msha-controller-operator-history
- **operator_operates_mine:** Salt Lick Coal Corp → Spruce Fork Mine No 1; 1983-12-08 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** L Nicholas  Stevens → Spruce Fork Mine No 1; 1983-12-08 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** L Nicholas  Stevens → Salt Lick Coal Corp; 1983-12-08 to current/open; source msha-controller-operator-history