Oficina Maria Elena, Saltpeter mine in María Elena, Chile

Oficina Maria Elena is a nitrate works in the Atacama Desert whose town plan follows the lines of the Union Jack, with four longer and four shorter sides. It was founded in 1926 as Coya Norte and renamed by founder Elias Anton Cappelen Smith after his wife Mary Ellen Condon. The plant remains in operation and is owned by SQM.

The site was founded in 1926 when the US-based Anglo-Chilean Consolidated Nitrate Corporation bought the assets of the British Anglo-Chilian Nitrate and Railway Company and expanded operations, replacing the Humberstone process with the Guggenheim process. The town was laid out to evoke the lines of the Union Jack, with four longer and four shorter sides.

The settlement displays housing, workplaces, and communal areas that reveal how miners and their families lived together in this remote desert region. Visitors can observe the daily routines and social structures that shaped life in northern Chilean mining communities.

Visits require advance planning since the location is remote and water should be brought for the desert environment. Travel from Antofagasta is possible but allows only limited day trips to this area.

The complex preserves working machinery and equipment from its operating period that demonstrate the technological level of nitrate production. These original installations give visitors direct insight into the industrial processes that were used at that time.