A mining field existed on the planet Thearterra, situated within the Unknown Regions. It began operations recently in 19 BBY. During that year, the Mitth and Ufsa families of the Chiss Ascendancy's ruling lineages competed for dominion over the field.
The existence of the mining field was initially revealed in an excerpt from Thrawn Ascendancy: Chaos Rising, which is the initial book in the Star Wars: The Ascendancy Trilogy series, which came out on July 8, 2021. The complete novel was then published on September 1 of the same year.