# Relationship history for MSHA mine 1200771

Current hierarchy: **Romas Robert → Parke West Materials → Parke West Materials**

- 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:** Legacy Vulcan Corp (Form:Vulcan Materials Co) → Parke West Materials; 1950-01-01 to 2007-11-15; source msha-controller-operator-history
- **operator_operates_mine:** Western Materials Div-Medusa Aggregates Company → Parke West Materials; 1950-01-01 to 1978-12-31; source msha-controller-operator-history
- **controller_controls_mine:** Medusa Corp → Parke West Materials; 1950-01-01 to 1978-12-31; source msha-controller-operator-history
- **controller_controls_operator:** Medusa Corp → Western Materials Div-Medusa Aggregates Company; 1950-01-01 to 1978-12-31; source msha-controller-operator-history
- **controller_controls_mine:** Crane Company → Parke West Materials; 1978-12-13 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Medusa Aggregates Company → Parke West Materials; 1979-01-01 to 1982-12-19; source msha-controller-operator-history
- **controller_controls_operator:** Crane Company → Medusa Aggregates Company; 1979-01-01 to 1982-12-19; source msha-controller-operator-history
- **operator_operates_mine:** Vulcan Materials Company → Parke West Materials; 1982-12-20 to 1988-03-24; source msha-controller-operator-history
- **controller_controls_operator:** Legacy Vulcan Corp (Form:Vulcan Materials Co) → Vulcan Materials Company; 1982-12-20 to 1988-03-24; source msha-controller-operator-history
- **operator_operates_mine:** Parke West Materials → Parke West Materials; 1988-03-25 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Romas Robert → Parke West Materials; 1988-03-25 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Romas Robert → Parke West Materials; 1988-03-25 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Vulcan Materials Company → Parke West Materials; 2007-11-16 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Vulcan Materials Company → Vulcan Materials Company; 2007-11-16 to 1988-03-24; source msha-controller-operator-history