# Relationship history for MSHA mine 4606161

Current hierarchy: **Costain Group PLC → Nix Mining Company → No 6 Surface 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:** Scholl Rex Et Al → No 6 Surface Mine; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Ashland Inc et al → No 6 Surface Mine; 1977-05-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Hobet Mining Inc → No 6 Surface Mine; 1980-05-01 to 1982-01-13; source msha-controller-operator-history
- **controller_controls_operator:** Ashland Inc et al → Hobet Mining Inc; 1980-05-01 to 1982-01-13; source msha-controller-operator-history
- **operator_operates_mine:** P & S Coal Company → No 6 Surface Mine; 1982-01-14 to 1986-02-23; source msha-controller-operator-history
- **controller_controls_operator:** Scholl Rex Et Al → P & S Coal Company; 1982-01-14 to 1986-02-23; source msha-controller-operator-history
- **controller_controls_mine:** Graybeal Carl N & Jack L Williams → No 6 Surface Mine; 1984-05-18 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** W & G Construction Company Inc → No 6 Surface Mine; 1986-02-24 to 1988-02-23; source msha-controller-operator-history
- **controller_controls_operator:** Graybeal Carl N & Jack L Williams → W & G Construction Company Inc; 1986-02-24 to 1988-02-23; source msha-controller-operator-history
- **operator_operates_mine:** Nix Mining Company → No 6 Surface Mine; 1988-02-24 to 1990-10-17; source msha-controller-operator-history
- **controller_controls_mine:** Jack L  Williams → No 6 Surface Mine; 1988-02-24 to 1990-10-17; source msha-controller-operator-history
- **controller_controls_operator:** Jack L  Williams → Nix Mining Company; 1988-02-24 to 1990-10-17; source msha-controller-operator-history
- **operator_operates_mine:** Nix Mining Company → No 6 Surface Mine; 1990-10-18 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Costain Group PLC → No 6 Surface Mine; 1990-10-18 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Costain Group PLC → Nix Mining Company; 1990-10-18 to current/open; source msha-controller-operator-history