# Relationship history for MSHA mine 3606912

Current hierarchy: **PT BUMA Internasional Grup Tbk → Coal Contractors (1991) Inc → William Socko Stripping**

- 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:** Joseph  Kovaleski → William Socko Stripping; 1973-12-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** J R K Construction Company → William Socko Stripping; 1979-12-01 to 1996-05-31; source msha-controller-operator-history
- **controller_controls_operator:** Joseph  Kovaleski → J R K Construction Company; 1979-12-01 to 1996-05-31; source msha-controller-operator-history
- **controller_controls_mine:** Bell Denis Inc → William Socko Stripping; 1992-10-26 to 2003-04-30; source msha-controller-operator-history
- **operator_operates_mine:** Coal Contractors (1991) Inc → William Socko Stripping; 1996-06-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Bell Denis Inc → Coal Contractors (1991) Inc; 1996-06-01 to 2003-04-30; source msha-controller-operator-history
- **controller_controls_mine:** Pen Carb Incorporated → William Socko Stripping; 2003-05-01 to 2007-11-12; source msha-controller-operator-history
- **controller_controls_operator:** Pen Carb Incorporated → Coal Contractors (1991) Inc; 2003-05-01 to 2007-11-12; source msha-controller-operator-history
- **controller_controls_mine:** Atlantic Carbon Group PLC → William Socko Stripping; 2007-11-13 to 2020-07-16; source msha-controller-operator-history
- **controller_controls_operator:** Atlantic Carbon Group PLC → Coal Contractors (1991) Inc; 2007-11-13 to 2020-07-16; source msha-controller-operator-history
- **controller_controls_mine:** ACG Holdco LLC → William Socko Stripping; 2020-07-17 to 2024-06-25; source msha-controller-operator-history
- **controller_controls_operator:** ACG Holdco LLC → Coal Contractors (1991) Inc; 2020-07-17 to 2024-06-25; source msha-controller-operator-history
- **controller_controls_mine:** PT BUMA Internasional Grup Tbk → William Socko Stripping; 2024-06-26 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** PT BUMA Internasional Grup Tbk → Coal Contractors (1991) Inc; 2024-06-26 to current/open; source msha-controller-operator-history