# Relationship history for MSHA mine 0504402

Current hierarchy: **Mexted Enterprises Inc; RGV LLC; Heartland Environmental Services LLC → Heartland Aggregate Mining → Merrill Pit**

- 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:** Merrill  Wright → Merrill Pit; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Universal Peat Sand & Gravel → Merrill Pit; 1989-07-01 to 2013-07-08; source msha-controller-operator-history
- **controller_controls_operator:** Merrill  Wright → Universal Peat Sand & Gravel; 1989-07-01 to 2013-07-08; source msha-controller-operator-history
- **controller_controls_mine:** Park County-CO → Merrill Pit; 1991-07-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Park County Road & Bridge Department → Merrill Pit; 2013-07-09 to 2024-12-03; source msha-controller-operator-history
- **controller_controls_operator:** Park County-CO → Park County Road & Bridge Department; 2013-07-09 to 2024-12-03; source msha-controller-operator-history
- **controller_controls_mine:** Heartland Environmental Services LLC et al → Merrill Pit; 2021-01-05 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Heartland Aggregate Mining → Merrill Pit; 2024-12-04 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Heartland Environmental Services LLC et al → Heartland Aggregate Mining; 2024-12-04 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** RGV LLC et al → Heartland Aggregate Mining; 2024-12-04 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Mexted Enterprises Inc et al → Heartland Aggregate Mining; 2024-12-04 to current/open; source msha-controller-operator-history