# Relationship history for MSHA mine 4608185

Current hierarchy: **Courtland  Helbig → Difficult Mining Inc → Johnstown 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: 2026-10-17T05:35:58.500035+00:00

## Valid-time edges

- **operator_operates_mine:** Linn Mining Company Inc → Johnstown No. 1; 1992-06-01 to 1995-10-29; source msha-controller-operator-history
- **controller_controls_mine:** James H  Atkinson → Johnstown No. 1; 1992-06-01 to 1995-10-29; source msha-controller-operator-history
- **controller_controls_operator:** James H  Atkinson → Linn Mining Company Inc; 1992-06-01 to 1995-10-29; source msha-controller-operator-history
- **operator_operates_mine:** Linn Mining Company → Johnstown No. 1; 1995-10-30 to 1999-04-22; source msha-controller-operator-history
- **controller_controls_mine:** Jeffrey D  Atkinson → Johnstown No. 1; 1995-10-30 to 1999-04-22; source msha-controller-operator-history
- **controller_controls_operator:** Jeffrey D  Atkinson → Linn Mining Company; 1995-10-30 to 1999-04-22; source msha-controller-operator-history
- **controller_controls_mine:** Courtland  Helbig → Johnstown No. 1; 1998-03-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Difficult Mining Inc → Johnstown No. 1; 1999-04-23 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Courtland  Helbig → Difficult Mining Inc; 1999-04-23 to current/open; source msha-controller-operator-history