Harkoum

Harkoum is a borderline M-class planet belonging to the Cardassian Union. Located in the binary Geilod system, the planet was an arid, desert world, with no indigenous sapient life. After the Dominion War, Harkoum temporarily became a protectorate of the Romulan Star Empire until such time as the newly-democratic Cardassian Union was able to reassert its sovereignty. 

During the 23rd century, the Cardassians established large-scale industrial operations on the planet, mining duranium and other materials. By the end of the century, the Harkoum had been thoroughly strip-mined and depleted of all important resources. Afterwards, it was mostly abandoned by the Union, and became the location of several prison facilities, including the Obsidian Order base Grennokar. These facilities were largely decommissioned by the time of the Dominion War. 

By the late 2370s, the planet's abandoned facilities proved to be useful to the Orion Syndicate for a variety of extralegal activities.