# Relationship history for MSHA mine 0404594

Current hierarchy: **Hugh Roy  Marshall → Marshall Earth Resources Inc → Shamrock Lode 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:** Hugh Roy  Marshall → Shamrock Lode Mine; 1980-02-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Phil Pollard → Shamrock Lode Mine; 1982-06-01 to 1991-08-26; source msha-controller-operator-history
- **controller_controls_mine:** Pollard Phil → Shamrock Lode Mine; 1982-06-01 to 1991-08-26; source msha-controller-operator-history
- **controller_controls_operator:** Pollard Phil → Phil Pollard; 1982-06-01 to 1991-08-26; source msha-controller-operator-history
- **operator_operates_mine:** Marshall Earth Resources Inc → Shamrock Lode Mine; 1991-08-27 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Hugh Roy  Marshall → Marshall Earth Resources Inc; 1991-08-27 to current/open; source msha-controller-operator-history