In the 1970s, Lepanto Consolidated Mining Company in a joint venture with Negros Occidental Copperfields Mines Inc. undertook exploration of the area. The drilling of 117 holes indicated a resource of approximately 92 Mt grading at 0.47% Cu at the DJ deposit, including some 6.6 Mt at 0.65% Cu of supergene mineralisation.
In 1980, the joint venture engaged Pincock, Allen and Holt of Denver to undertake a feasibility study on a 14,000 tpd mining and milling operation. The study showed the deposit to be economically viable and construction commenced in 1982. However, in 1983, the project was abandoned due to a decline in copper prices.
In 1991, Colet Mining and Development Corporation entered into an operating agreement with Selenga Mining Corporation (Seminco), a Philippine registered company which was owned by Tequila Copper Corporation of Toronto at the time. Seminco undertook induced polarisation (IP) and magnetic geophysical and geochemical soil surveys that led to the A1 deposit and other satellite deposits being identified. Seminco also drilled an additional four diamond holes at the DJ deposit.
In 1995, International Pursuit Corporation entered into a joint venture with Tequila and through its subsidiary undertook exploration on the property, including drilling, soil sampling and IP geophysical surveys. Smaller copper soil anomalies were defined to the northwest of the DJ deposit and a broad distinct anomaly covering the A1 deposit area was identified. The IP survey produced anomalies in the A1 deposit area and to the southwest of the DJ deposit. These anomalies (especially the IP anomaly to the southwest of the DJ deposit) still maintain exploration potential and follow up exploration has been recommended.
In 2000, Zinc and Copper Corporation of Australia took over the Hinoba-an Project and conducted further desktop studies until the project was acquired by Copper Resources Corporation in 2005. In 2007, a scoping study on the project was completed. In 2009, Solfotara Mining Corp. acquired the Hinoba-an Project and subsequently sold the project to CDC in exchange for an equity investment in the Company which was partially distributed to Solfotara shareholders.
After acquiring the Hinoba-an Project in 2009, CDC undertook a drilling programme and completed an updated scoping study in July 2010 and a comprehensive technical report in March 2012.
Over 100,000 metres have been drilled on the Hinoba-an property. The types of drilling include diamond drilling, reverse circulation (RC) drilling and drill holes drilled for geotechnical information.