The Onu-Koro Mining Guild was a union of miners in Onu-Koro. It was represented on the Onu-Koro Council. The leader of this organization is unknown. It complained that the lack of Lightstones in the city had reduced production by seventy-five percent. It also warned that it could not continue to allow its workers to labor in the dark conditions and urged that the project to finish the Le-Koro Highway be sped up. It had the backing of the Onu-Koro Trading Guild in this demand.