# Relationship history for MSHA mine 2600397

Current hierarchy: **N A Degerstrom → N A Degerstrom Inc → Rossi 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

- **controller_controls_mine:** N A Degerstrom → Rossi Mine; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Tom Norris Inc → Rossi Mine; 1950-01-01 to 1990-07-30; source msha-controller-operator-history
- **controller_controls_mine:** Thomas D Norris → Rossi Mine; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Thomas D Norris → Tom Norris Inc; 1950-01-01 to 1990-07-30; source msha-controller-operator-history
- **controller_controls_mine:** Halliburton Company → Rossi Mine; 1978-03-09 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** S M & S Neilsen Exploration → Rossi Mine; 1990-07-31 to 1992-11-15; source msha-controller-operator-history
- **controller_controls_mine:** Steve  Neilsen → Rossi Mine; 1990-07-31 to 1992-11-15; source msha-controller-operator-history
- **controller_controls_operator:** Steve  Neilsen → S M & S Neilsen Exploration; 1990-07-31 to 1992-11-15; source msha-controller-operator-history
- **operator_operates_mine:** Brown & Root Inc → Rossi Mine; 1992-11-16 to 2001-08-20; source msha-controller-operator-history
- **controller_controls_operator:** Halliburton Company → Brown & Root Inc; 1992-11-16 to 2001-08-20; source msha-controller-operator-history
- **operator_operates_mine:** N A Degerstrom Inc → Rossi Mine; 2001-08-21 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** N A Degerstrom → N A Degerstrom Inc; 2001-08-21 to current/open; source msha-controller-operator-history