# Relationship history for MSHA mine 0405271

Current hierarchy: **Terry E  Smith → Essayons Inc → Frontier Kolberg Screening Plant #2**

- 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:** Bruce O  McIntosh et al → Frontier Kolberg Screening Plant #2; 1980-02-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Mc Intosh Construction → Frontier Kolberg Screening Plant #2; 1995-07-01 to 1997-01-28; source msha-controller-operator-history
- **controller_controls_operator:** Bruce O  McIntosh et al → Mc Intosh Construction; 1995-07-01 to 1997-01-28; source msha-controller-operator-history
- **operator_operates_mine:** Essayons Inc → Frontier Kolberg Screening Plant #2; 1997-01-29 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Terry E  Smith → Frontier Kolberg Screening Plant #2; 1997-01-29 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Terry E  Smith → Essayons Inc; 1997-01-29 to current/open; source msha-controller-operator-history