# Relationship history for MSHA mine 3610409

Current hierarchy: **Lance  Birchard → L & D STONEWORKS INC. → PORTABLE PLANT 1**

- 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:** Dave  Owen et al → PORTABLE PLANT 1; 2004-04-20 to 2024-01-03; source msha-controller-operator-history
- **operator_operates_mine:** L & D STONEWORKS INC. → PORTABLE PLANT 1; 2022-11-28 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Dave  Owen et al → L & D STONEWORKS INC.; 2022-11-28 to 2024-01-03; source msha-controller-operator-history
- **controller_controls_operator:** Lance  Birchard et al → L & D STONEWORKS INC.; 2022-11-28 to 2024-01-03; source msha-controller-operator-history
- **controller_controls_mine:** Lance  Birchard → PORTABLE PLANT 1; 2024-01-04 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Lance  Birchard → L & D STONEWORKS INC.; 2024-01-04 to current/open; source msha-controller-operator-history