Mineral Processing Circuit

The Rosh Pinah processing plant has been in continuous production since 1969. It utilizes conventional size reduction and mineral beneficiation unit processes to treat ore from the Eastern and Western Orefields. The plant currently treats 0.68 to 0.71 Mtpa, producing approximately 50 to 60 ktpa of zinc concentrate and 4.5 to 7.5 ktpa of lead concentrate.

Nautilus Minerals’ preliminary economic assessment for the Bismarck Sea project produces three streams with no processing chemicals, and meets the transportable moisture limit by testing on board.

This NI 43-101 Technical Report presents a Preliminary Economic Assessment (PEA) for the Record Ridge Project in British Columbia, Canada, developed by WHY Resources. The study outlines a process to extract magnesium from magnesium oxide bearing material with a treatment rate of 3,000 tonnes per day. The proposed flowsheet utilizes a hydrometallurgical approach involving crushing, grinding, and sulfuric acid leaching to recover magnesium.

This section of the NI 43-101 Technical Report details the metallurgical testing and process route selection for the COSE Project. SGS Minerals Services in Santiago, Chile conducted a series of tests on 25 composite samples derived from 70 individual samples across oxidized, partially oxidized, and non-oxidized portions of fault-hydrothermal breccia hosted and veinlet gold mineralization. The testing included screen fire assays, gravitational concentration using a Knelson concentrator, and bottle roll cyanide leaching tests.

This technical report details updated diamond drilling, metallurgical testing, and mineral resources for the Klaza Project in Yukon, Canada. The report outlines a processing flowsheet that incorporates gravity pre-concentration to reduce grinding circuit tonnage by approximately 50%. The process involves crushing run-of-mine material to 9.5 mm, screening fines, and gravity concentration on the coarse fraction. The resulting concentrate is blended with fines and fed to a grinding circuit followed by sequential rougher and cleaner flotation to produce gold-rich lead and zinc concentrates.

The report details the recovery methods for the Copper Creek Project, outlining two distinct process flowsheets designed to treat mineralized materials from various deposits. The primary process utilizes froth flotation to beneficiate copper, molybdenum, and silver from transitional and sulphide materials, with a nominal throughput of 30,000 t/d. The second process extracts copper from oxide materials via heap leaching, solvent extraction, and electrowinning, with a nominal throughput of 6,850 t/d.

The Lost Creek ISR Uranium Property utilizes an In Situ Recovery (ISR) method for uranium extraction, with a processing plant operational since August 2013. The facility comprises four major solution circuits: uranium recovery via ion exchange (IX), elution to strip uranium from resin, yellowcake precipitation, and dewatering, drying, and packaging. The process involves pumping production fluid containing dissolved uranyl carbonate to the plant, where uranium is extracted onto resin, eluted, and precipitated using hydrogen peroxide and sodium hydroxide.