The style of mineralisation within fractured acidic pyroclastics is not a common form of uranium mineralisation. The main uranium mineral present is meta-autunite concentrated as disseminations and sometimes massively along fractures. Hence the exploration is based on ground radiometrics followed by evaluation drilling over the potential host rocks of the mineralisation.

The Andes represents a large anticlinorium complicated by a series of faults and intrusions, with the flanks of this superstructure are made up of the coastal Mesozoic and eastern Palaeozoic belts. The Andes represent the Late Tertiary and Quaternary rejuvenation by block faulting of an eroded early Tertiary folded mountain range which occupied the axis of Palaeozoic and Mesozoic geosynclines. Topographically the mountains consist of a central dissected plateau, the Intermontane Depressions and Altiplano enclosed by narrow ranges, the Western Cordillera and the Eastern Cordillera.

In the area of interest, late Tertiary tuffs, ignimbrites and associated sediments are preserved in a northwest-southeast trending graben. Much of the Early Tertiary and Mesozoic cover was eroded prior to deposition of the pyroclastics so they were deposited in part directly on the Palaeozoic rocks including Late Palaeozoic intrusives (Hercynian granites) and extrusives (Mitu volcanics).

The known uranium occurrences in the Macusani region identified by IUREP are associated with these Pliocene and Miocene epoch Quenamari Formation tuffs, ignimbrites and interbedded sediments. Other uranium mineralisation was indicated by IUREP (1984) to be hosted in acidic volcanic rocks of rhyolite composition that cover large areas of the Macusani Plateau in horizontally bedded formations from surface to a depth of about 100 m but these appeared to be lenticular or confined to fracture zones (Young, 2013).

Uranium mineralisation is found in acidic volcanic pyroclastic rocks of rhyolite composition that cover large areas of the Macusani Plateau which are preserved in a NW-SE trending graben within the Andes. These pyroclastic rocks are dated between 10.0 and 6.7 Ma. Uranium mineralisation is found concentrated along steeply dipping fractures but constrained within horizontal or sub-horizontal zones and is disseminated into the surrounding host rock.

The host rocks and PEM are composed of an acidic tuff (Thatcher, 2011) (19) with pyroclasts of size 60 mm to sub-macroscopic. The main minerals constituting the tuff are quartz, orthoclase and plagioclase in a groundmass of amorphous glass. Crude bedding is evident in some outcrops, and is based on “strata” containing larger and smaller pyroclasts. Overall the uranium mineralisation is interpreted to be hosted in a flat dipping acidic tuff.

Uranium mineralisation is observed in these pyroclastic host rocks, and at a local scale is found concentrated along fractures and disseminated into the surrounding host rock. Zones in which the uranium mineralisation (either fracture and / or dissemination) is more concentrated, are identifiable by analysing uranium distribution profiles in drillhole core, and are occasionally observable in outcrop. These mineralised zones, referred to locally as “Manto’s”, typically have a horizontal or sub-horizontal orientation, and can vary from several metres to tens of metres in thickness.

The petrography of the samples analysed by Thatcher (2011) indicates that the acid volcanics rystal lapilli tuffs) can have varying composition from rhyolite to dacite to latite which supports the likely presence of stratigraphic layering of the volcanic pile as noted in by Cheilletz et al (1992).

CORACHAPI COMPLEX
TMC undertook Mineral Resource estimates for the Corachapi deposit in 2010, and at that time, mineralisation was interpreted to be hosted in a single, sub-horizontal mineralised zone, which was oriented in a northeasterly direction.

COLIBRI COMPLEX
Mineralisation at the Colibri II & III and Tupurumani deposits is interpreted to be hosted in a subhorizontal, near surface zone, with a dip of approximately 2° - 3° to the northeast. The base of the near surface high-grade zone of mineralisation has a depth of approximately 35 m below surface at Tupuramani and 50 m below surface at Colibri II & III. Lower grade mineralisation is found below the base of the high-grade zone.

KIHITIAN COMPLEX
Within the Kihitian Complex, mineralisation is broadly contained within two distinct zones, referred to as Level A, an upper horizon and Level B, the lower horizon. A dip of 3° towards the southeast is interpreted. Most of the mineralisation for the Complex lies in Level B, while Level A has more sporadic and less continuous mineralisation. The Chilcuno Chico and Tantamaco deposits host both zones while at Quebrada Blanca the mineralisation occurs stratigraphically in Level B and the sparse nature of drilling on the Tuturumani deposits enabled the definition of only the Level A. The Tuturumani deposit has been minimally explored, thus Level B has not been fully tested by drilling. The contact between Level A and Level B zones has a characteristic grade spike which has been consistent but not continuous across the four deposits. The depth of mineralisation is related to the topography with maximum depths being 200 m and 260 m for Level A and Level B respectively.

ISIVILLA COMPLEX
Uranium mineralisation at the Calvario I, Puncopata, Calvario Real and Isivilla deposits is evident in two sub-parallel, near-horizontal zones, locally referred to as levels, separated vertically by 30 m of barren rhyolite.

At the Isivilla and Calvario Real deposits, two distinct zones referred to as Level A and Level B have been identified. The two levels have a highly diffuse contact with an irregular rhyolite parting. Both levels have been noted to outcrop. Although there are localised variations, generally the contact lies flat dipping up to a maximum of 4° to the northeast. The maximum depth of Level A is approximately 60 m and that of Level B approximately 130 m. During correlation, mineralisation in the Puncopata deposit was noted to be localised exclusively to Level B while in contrast, at the Calvario I deposit, mineralisation is localised exclusively to Level A horizon.

At the Calvario I and Puncopata deposits, the flat-lying interpretation of the mineralised levels is supported by radial radiometric anomalies which encircle the hilltop at the same elevation as the mineralised levels have been interpreted to outcrop (Figure 10-5). Although similar radiometric survey data is absent for the Calvario Real and Isivilla deposits, the extrapolation of the elevation of mineralisation coincides with the elevations as identified from the radiometric data available at the Calvario I and Puncopata deposits.

The uranium mineralisation occurrence is highly isolated although correlatable with the mineralisation in the Puncopata deposit to the north and Isivilla deposit to the south. Mineralisation occurs at variable depths from 30 m to 80 m.

CORANI COMPLEX
The Corani Complex is also interpreted to have two levels, Level A and Level B. These have an approximate dip / dip direction of 3°/157°. At the Calvario III and Nueva Corani deposits, mineralisation occurs within Level A, with less continuous mineralisation in Level B. At the Calvario II deposit, only Level B has been preserved, and Level A had been eroded.

SAYAÑA COMPLEX
The local dip / dip direction within the Sayaña Complex is 5°/117°. Two layers are identified in the geological logging information provided, comprising a polymictic rhyolite upper horizon and a monomictic rhyolite lower horizon (Henkle, 2014) (14). Analysis of the intersections rev

A base case contains of 101 Mt of Mineral Resources that are projected to be extracted from open pits and 8.23 Mt from underground mining. The base case open pits are planned to extract 30 000 tpd of PEM through conventional drill/blast and truck/shovel methods. The base case includes a LOM average of 10.9 Mt/a at 289 ppm U3O8 for a total of 31 400 t of contained U3O8 metal and 61.0 M lbs of recovered U3O8.

The Colibri, Kihitian and Isivilla Complexes (Complex 2, 3, and 4 respectively) are planned to be recovered from open pit mining operations. Due to the orientation and topography of the Kihitian Complex, significant Mineral Resources are uneconomic to mine via the open pit method due to the excessive stripping costs and, as such, an underground operation is planned for mineralised material above cut-off.

The open pit fleet will move PEM to either the processing area or a mobile crusher, depending on proximity. An allowance has been included in the open pit fleet to haul underground PEM to a central crushing plant.

The Mineral Resources available for underground mining that forms the project LOM plan are contained within a portion of the Mineral Resource block model that is excluded from current economic open pit limits, but which is judged potentially mineable by underground methods. These Mineral Resources contain a significant quantity of Inferred material. For conceptual production, Inferred material has been included within the design and includes estimates of mining dilution and mining recovery.

The proposed underground mine design supports the extraction of 2 700 tpd of PEM through room and pillar mining utilising continuous miners. Paste back fill has not been considered for the design, instead in-situ pillars are planned to be used for support. Conveyor systems have been incorporated for the majority of mining activities.

Material handling from the underground workings to the surface is based on conveyor haulage through the workings, with PEM being hauled directly from the underground to the ROM stockpile through the underground access. Drill and blast equipment has been included (Jumbo / Charge Wagon / Wheel Loader) to allow for the establishment of areas via drill and blast to allow continuous mining.

Mining ventilation will be accomplished by two dedicated exhaust shafts to surface, each equipped with modern fans that will draw fresh air in at the main entrance and through the workings of the mine before being exhausted through the dedicated return airways to minimise exposure to radiation. The two exhaust shafts are located within the mining areas, in the northern and southern extents of the mine layout.

Current underground mining is planned to use modern continuous miners assisted by conveyors for material handling. In addition to a continuous mining unit, an underground drilling rig has been included for ground support and minor drill and blast duties where required. A wheel loader has also been included for clean-ups and associated works if required. Equipment utilisation and availability was modelled at 90 % respectively.

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The proposed method of recovery is based on the developed production schedule of the PEM. The proposed method includes crushing and stacking PEM onto a heap leach pad which is irrigated with an acidic solution to dissolve the uranium. The leach solution would then pass through ion exchange (IX) columns to recover the dissolved uranium and solvent extraction (SX) to recover uranium from the IX eluate to reduce acid consumption. The SX product solution then passes through precipitation to yield a yellowcake precipitate, which is thickened, filtered, dried and packaged for dispatch. Interpretation of metallurgical testwork results determined a processing recovery rate of 88 %, resulting in an average annual production of 6.08 M lb U3O8.

The chemistry of the acid leach is a process of uranium being dissolved in dilute sulfuric acid to form uranyl sulfate.

Operational heap cells are paired during leaching depending on the amount of time the cell has been under irrigat ........