According communication of Veronica Castillo Rojas, public relations of the "Intendencia de la II Región", firstly from a fax (last days of 1997) and later by letter undated I received 20 January 1998, the region has a "logotipo de identidad regional" (regional logo) created in a public contest organized in Octuber 1996. This logotype is now pictured in a white flag, that must be a provisional regional flag like was (or still is) the blue flag with the seal. Jaume Ollé, 17 January 2015
This design matches the one shown in the 2008 photo taken at the National Congress building (in Wikimedia Commons); an image of the logo is at the official website (this looks very much like Jens’ source).
The logo shows stylized images of important elements of local history and economy; these elements are made of simple shapes in solid colors, mostly loose on the white background. It is enscribed in a square and has lettering above and below: "GOBIERNO REGIONAL DE" and "ANTOFAGASTA," proportionedly sized to fill one line the length of the logo, wide set in bold serifless condensed reddish-brown capitals. The logo itself shows as its main element a reddish-brown diamond (a square standing on its corner) with white double edge and a golden yellow loaded mine wagon. This diamond defines four triangular quadrants: On the upper fly, a darkest blue rendition of an observatory against a night sky with stars, an eclipse, and a comet; on the lower fly, a church against a light blue sky, a green tree, and a reddish-brown cave entrance (?); on the upper hoist, a factory with green walls, golden yellow windows, and white and reddish-brown stripped smokestack; on the lower hoist a cargo ship with reddish-brown crane, and darkest blue hull, windows, and funnel. António Martins-Tuválkin, 1 June 2016
This flag is similar to the Intendent Standard, in that both place the National Coat of Arms on a yellow disc on a blue field. But this flag has a thick red ring bearing the inscription REGION DE ANTOFAGASTA CHILE, so you know where you are. Alex Garofolo, 6 February 2016