troops on the riverbank. Getty informed Walke that Marmora and Signal could clear the mines from the river if accompanied by larger vessels that could provide covering fire against any Confederate troops on the riverbanks; the water level in the Yazoo had risen enough to accommodate larger vessels. The next day, Marmora, joined by Signal, Queen of the West, and the ironclads USS Cairo and USS Pittsburgh, moved up the Yazoo to remove the mines. Marmora and Signal were tasked with destroying the mines, with all of the ships' commanders instructed to avoid bringing their ships close to the mines. The expedition entered the Yazoo at around 8:00 am, and at either 10:00 am or 11:00 am met a skiff containing an African American and a white plantation overseer. The overseer admitted to having knowledge of the location of the mines and as a result was arrested. The vessels continued ahead to where the mines were. Cairo heard men from Marmora shooting at objects in the river and continued ahead thinking the tinclad was under assault. Both Cairo and Marmora put small boats into the water to investigate the mines, which were found to be connected to the shore by wires. Cairo and Marmora began to maneuver after launching the boats, and the Confederate batteries on Drumgould's Bluff fired on the vessels at long range. Cairo then struck two mines and quickly sank. None of the crew of Cairo were killed, and they were picked up by the other Union vessels. Chickasaw Bluff and Fort Hindman The surviving Union vessels returned to Walke's main force. Upon their return, the commander of Cairo was told to put his crew on Marmora and take her up the Mississippi River to Cairo, where he was to report to Porter. Marmora met Porter and the gunboat USS Black Hawk on December 17 while moving upriver. Porter elected to not open a court of inquiry against the commander of Cairo, and ordered the mine clearing to be completed. The crewmen of Cairo were landed at Cairo on December 18. Marmora then helped other Union vessels clear the mines out of the river. The naval vessels also probed along the Yazoo in support of Union Army movements in the area. On December 27, Sherman landed army troops in front of Chickasaw Bluff, while Marmora joined six other naval vessels in advancing upriver against Drumgould's Bluff. The