7348-II is a class M planet, the second planet located in System 7348, near the Federation-Klingon border. The planet is rich in many natural resources, including dilithium, and was home to a race of primitive Klingons.
At some point prior to 2266, Councillor Duras of the Klingon Empire learned of the primitive Klingons who lived on the planet, and of the abundant resources which would prove vital in any coming war with the Federation. Due to the planets location inside Federation space, Duras made an agreement with the Orions which meant that they would operate the deep mining facility on the planet and extract all the raw materials they could from the planet, regardless of the environmental effects on the planet or its inhabitants. (TOS novels: Demands of Honor, Killing Blow)
When Starfleet learned of the "Orion" operation in late 2266, they dispatched Captain James T. Kirk and the USS Enterprise to the planet to shutdown the operation and possibly learn of any Klingon involvement. Kirk sent a massive security force down to the surface, and with the help of the local clans, led by Gorath, they were able to overcome the Orion forces. (TOS novel: Killing Blow)
A few months later, the IKS D'k Tahg was dispatched on a contact mission to the planet with Councillor Duras aboard. Because of the planet's location, Starfleet agreed to the mission, but sent the Enterprise to monitor the diplomatic mission. While the two starships were in orbit, it transpired that Duras had worked with a local clan leader, Gurn, to retake control of the mines and once again begin to mine dilithium for the Empire. Officers loyal to Duras also wrestled control of the D'k Tahg from Captain Koloth and launched an unsuccessful attack on the Enterprise. Thankfully the mine was recaptured and shutdown after a pitched battle with Starfleet security forces, Koloth's officers, and loyal natives, against Duras's officers and native forces loyal to Gurn. (TOS novel: Demands of Honor)