The Ok Tedi mining operations are centred on the Mt Fubilan deposit located in the Star Mountains of the Western Province. Mt Fubilan is a rich coppergold-silver deposit with several phases of mineralisation centred on two intrusions, known as the Fubilan monzonite porphyry, located in the northern half or Centre Pit area and the Sydney monzodiorite stockworks with subsequent alteration in the south. Majority of the ore is found in the sulphide skarns, located adjacent to the intrusions along the contacts with the limestone and siltstone units. In 2021, OTML exploration activities concentrated on near mine targets within SML1. Due to COVID-19 travel restrictions all regional exploration programs were put on hold. A diamond drilling program completed 14 holes into the New York breccia and other breccia targets between Wellington and Townsville. The drilling confirmed an increase in mineralisation at both targets. A soil sampling program was also conducted north of Sulphide Creek in areas previously not tested by geochemical sampling. This program will be completed in early 2022 and covers an area referred to as the Wellington Corridor. OTML continues its resource definition drilling within the Fubilan mine area and on advanced prospects within SML1 to replace mined reserves and improve resource confidence. Within SML1, drilling focused on the New York breccia and other breccia targets in an area between Wellington and Townsville, now referred to as Gilor Corridor. A total of 14,136m of diamond drilling was completed. Most drilling was within the New York breccia, but targets were also tested in the Wellington and Gilor areas. A soil sampling program was also conducted north of Sulphide Creek in areas previously not tested by geochemical sampling. This program will be completed in early 2022 and covers an area referred to as the Wellington Corridor. NEW YORK BRECCIA Two high-capacity diamond rigs capable of drilling to 1,500 m were deployed in New York to test the deeper zones of the breccia pipe. Drilling of the New York breccia target accounted for over 80% of the total metres drilled for the year. Drilling is expected to be reduced in Q1 of 2022. WELLINGTON Additional drilling at Wellington increased the known skarn tonnage and grades from infill or extensional drilling. New structural targets were also identified at depth which appear to have a controlling effect on copper and gold grades. These new structural zones are currently being tested and this new target has been termed “Wellington Deeps”. GILOR BRECCIA Drilling of the Gilor breccia target was undertaken in 2021 with two holes completed. Drilling conditions were extremely difficult and planned depths to the breccia target could not be achieved. Hole collars have been moved and additional holes will be drilled.

Mining of the Mt Fubilan Ore Reserves continues to be carried out as a large open pit operation. Mining is conducted using conventional drill and blast techniques, with shovel and excavator loading equipment. Ore is mined and transported to a primary crusher as first stage processing or to a Run of Mine stockpile, where blending of various ore types can take place. Waste rock is characterised according to its Acid Rock Drainage (ARD) potential and disposed of in one of five waste dumps. Limestone waste rock is selectively dumped together with potential ARD waste rock to neutralise acid production.

The pit design and pit sequencing has been developed to maximise value while meeting environmental constraints agreed with mine-affected communities.

With approximately 9,000 mm of rainfall per annum, incident rainfall and runoff contributes significant volumes of free water draining into the pit. Rainwater also permeates into the rock mass contributing to instability due to increased pore pressure.

Comprehensive monitoring of hydrological and geotechnical factors are incorporated in mining strategy and plans to ensure safe operations.

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OTML’s business operations are centred on the Mt Fubilan deposit located in the Star Mountains. The deposit is mined as a large open pit with a flotation processing plant capable of treating in the order of 22 to 24 million tonnes per annum (Mtpa), and currently recovering copper and gold into a saleable concentrate using conventional technology. The throughput rate is highly dependent on the ore lithology delivered from the mine. The concentrate product contains approximately 25% copper with gold content in the range of 15 to 25 g/t.

Ore is mined and processed at an onsite flotation processing plant capable of treating up to 24 million tonnes per annum (Mtpa). The plant currently recovers copper, gold and silver into a saleable concentrate.

The primary ore is crushed and ground using Semi-Autogenous Grinding and Ball mills to a final grain size of approximately 180 microns.

The finely ground material is treated in two mineral floatation circuits to e ........