DEPOSIT TYPES
The Blanket orebodies comprise up to 10% of precious metals. The Blanket mineralisation is hydrothermally emplaced and associated with the regionally developed D2 deformation characterised by areas of high strain wrapping around relatively undeformed remnants of the original basaltic flows. Wider orebodies occur within the more ductile tensional high strain areas. Two main types of mineralisation are recognised at Blanket, namely Disseminated Sulphide Reefs (DSR) and quartz-filled reefs and shears. A third type of mineralisation may be evidenced in the form of auriferous sulphide minerals as a replacement of the iron-rich minerals along the hinges of the folds in BIF.

MINERALISATION
Mining at Blanket occurs over a 3 km strike that includes from north to south, the deposits of Lima, Eroica, Sheet, AR Main, AR South, Feudal, Blanket Section (Blanket 1 to Blanket 6) and Jethro. The main Blanket underground workings are connected to Lima by a 2 km long haulage which follows the strike of the main fabric.

Wall rock alteration typically comprises silica-pyrite-muscovite within a broader carbonate alteration halo. Quartz-carbonate altered rock forms the most commonly recognised alteration assemblage. Gold is deposited at crustal levels within and near the brittle-ductile transition zone at:-
• depths of between 6 km and 12 km;
• pressures between 1 and 3 kilobars; and
• temperatures between 200ºC and 400ºC.

The deposits may have a vertical extent of up to 2 km, demonstrate extensive down-plunge continuity, and lack pronounced zoning. The ore mineralogy is dominated by gold, pyrite and arsenopyrite. Subordinate minerals such as galena, chalcopyrite, pyrrhotite, sphalerite, tellurides, scheelite, bismuth and stibnite also occur. Sulphide mineralogy commonly reflects the litho-geochemistry of the host rock with arsenopyrite being the most common sulphide mineral in metasedimentary host rocks and pyrite or pyrrhotite being more typical in metamorphosed igneous hosts. The gangue and alteration mineralogy are dominated by quartz and carbonate (ferroan dolomite, ankerite, siderite, calcite) with subordinate albite, fuchsite, sericite, muscovite, chlorite and tourmaline.

Two quartz-filled shear zones are mined, namely the Blanket Quartz Reef (“BQR”) and the Eroica Reef, which have long strike lengths but are not uniformly mineralised although continuous pay shoots of over 100 m on strike are seen. Gold grade fluctuations are more extreme in the quartz reefs than in the DSR type reefs but on average these quartz shears have higher grades and are used as a sweetener of ore to the mill.

BLANKET QUARTZ REEF
The BQR strikes some 500 m on surface and is up to 5 m wide, diminishing with depth, dipping 55°W. It displaces the DSR type orebodies with an apparent reverse movement of up to 250 m. Mineralisation in the BQR is not uniform and comprises native gold with galena. Arsenopyrite is more dominant down-dip. Economic mineralisation is restricted to three 90 m pay shoots.

LIMA
Lima is situated 2 km north of the Blanket Section and an underground haulage links the two mines. Like the Blanket Section orebodies, the Lima orebodies developed in very high-strain areas. The main shoots are the Hanging Wall and Interlimb. Mineralisation in the Hanging Wall limb comprises pyrite with subordinate arsenopyrite in cleavage planes within pervasive biotite/chlorite alteration. The Interlimb is characterised by a centrally silicified core with pyrite and arsenopyrite constituting the main sulphides.

EROICA
The Eroica orebody lies approximately 1,300 m north of the Blanket Section orebodies and renowned for its high native gold content. It dips at 65°W and has a strike length of 300 m in a northerly direction. The Eroica orebody is hosted in a high-strain area where the shear is up to 15 m wide. Brown carbonate alteration characterises the shear in strong association with biotite development. The orebody is defined by thin silicified stringers that develop into swells of up to 5 m in width. The silicification shows pinch and swell both on strike and down-dip, resulting in a series of dismembered silicified pods developed within a particular shear. The biotite and carbonate alteration, together with the silicified stringers, form marker links between the dismembered pods. Finely-disseminated arsenopyrite, pyrite and pyrrhotite are associated with the gold mineralisation.

SHEET
The Sheet orebody lies about 500 m south of Eroica and is a typical example of a fault controlled mineralisation. It comprises of at least three stepped-out, sinistrally displaced and highly silicified hornblende-chlorite schist fault blocks . The orebody was subjected to both strike and “east-west” dip faulting, resulting in major bifurcation of the orebody up-dip into highly fractured North and South orebodies with variable dips. As with the other DSR orebodies at Blanket Mine, the less disturbed Sheet orebody downdip extension has a 60-65°W dip and a fabric that is sympathetic to the north-northwest regional shear. The orebody can attain widths and strike lengths of up to 15 m and 60 m respectively. Mineralisation is associated with finely disseminated arsenopyrite. The orebody was mined between 230 m Level and 870 m Level on separate dismembered shear zones.

AR OREBODIES
AR is a “Z”-shaped mineralised zone and consists of two separate orebodies (AR Main and AR South) with widths up to 30 m as a result of tectonic thickening from faulting and folding. The mineralised zone has no known surface expression and appears to form a ‘peak’ under the regional dolerite sill just above 9 Level some 500 m north of the Blanket Section orebodies. From this point the body splits into two the ore shoots of AR Main and AR South, which plunge 55°W and 58°SW respective.

AR Main
AR Main is a DSR-type orebody and occurs within a broad shear envelope in pillowed metabasalts, which is generally irregular in plan and bounded by shears that assist in defining the limits of the mineralisation. At 750 m Level, a shear disrupts the bodies causing the plunge to flatten to the west. The orebody strikes between 40 m and 60 m with an average width of 30 m at the centre of the envelope (MSA, 2011).

AR South
AR South plunges southwest, trending towards the Blanket 2 orebody at depth. AR South is also developed within a broad shear zone and is more pipe-like than AR Main. Its maximum thickness is approximately 50 m and high grade sections are defined by silicification and arsenopyrite.

FEUDAL
Occurring in the hanging wall of the Blanket-Lima strike about 900 m northwest of Jethro is the almost mined out “outlier” Feudal orebody. The orebody is interpreted to be located at the focal point of two Blanket-Lima strike transgressing shears, namely the Blanket-Feudal and Jethro-Feudal shears. The known orebody (surface outcrop to 7 Level for a 200 m lift) is now mined out.

BLANKET SECTION
The Blanket Section comprises six orebodies, namely Blanket 1 to Blanket 6, which occur some 500 m south of the AR orebodies. On average, the orebodies dip 80°SW. The reef has a shallower dip than the DSR bodies, but plunges in the same direction so that it progressively advances towards them with depth, displacing Blanket 2, 3, 1, 4. Blanket 2 reappears on the footwall of the BQR and is established on the 630 m Level through to the 870 m Level.

JETHRO
The Jethro orebody is located some 400 m south of the Blanket Section. The north-south striking Jethro orebody dips near vertical in a westerly direction and tends to roll over locally.

Blanket Mine uses two mining methods which are well suited to the nature of the greenstone belt deposits. The orebodies range from generally steeply dipping sheet-like deposits of a few meters in width, to pipeshaped and massive deposits with widths more than 50 m. The general practice on Blanket Mine is to implement one of two tailored mining methods, determined mainly by the width of the mineral deposit.

The two mining methods utilised are:-
• Long-hole stoping in wider mineral deposits (orebody widths generally more than 3 m); and
• Underhand stoping in narrow mineral deposits (orebody widths generally less than 3 m).

LONG-HOLE STOPING
Blanket mine uses long-hole stoping in the orebodies with a width greater than 3 m.

To access the orebody, crosscuts are developed from the tramming haulage to the extraction haulage which is located approximately 15 m from the orebody. Drawpoint crosscuts are developed at 15 m intervals along the extraction haulage which provide access to the drawpoints. A twin raise system is developed upwards to establish a sliping point for the development of the sub-drive. One raise serves as an access raise, while the other serves as an orepass to handle ore from the sub-drive development. The twin raise system is developed from one sub-drive to the next for the entire 120 m lift.

Drawpoint raises are established at 15 m intervals along the width of the orebody. A lead angle of 45 degrees is always maintained for the sub-drive development, with the bottom most sub-drive (lead drive) leading. Production faces have a lead angle of 72 degrees with the bottom most production face leading. Mining of the orebody is done in retreat from the one extreme end of the orebody to the other along its width.

Coning is done from the coning level and can only commence once sufficient raises for access and ore handling have been developed and holed into the sub-drive. Once coning starts, the raise can no longer be used as an access way. As a rule of thumb, four cones are established before any production may commence. Production drilling is done in a retreat fashion from the orebody limit and drilling is done top down with Seco S 36 drifter machines. Depending on production requirements, multiple sub levels may be mined simultaneously. The orebody width will ultimately determine the width of the stoping panel. Ore will then be extracted from the stope drawpoints via the lower extraction haulage using mechanical loaders. The ore is then loaded onto granby cars for transportation to the station orepasses.

UNDERHAND STOPING
Conventional underhand stoping is used in orebodies with a width less than 3 m This mining method implies that the block of ore is mined. Underhand stoping is particularly suitable for steeply dipping, narrow orebodies and allows for better control of the stoping width and dilution. Stoping preparations commence by mining slot raises at 15 m intervals along the extraction haulage from the footwall of the orebody. Development within the orebody is the same as in the long-hole stoping sections, with the difference being that boxes are mined instead of drawpoints. Upon establishment of sufficient slot raises, production commences with sliping around the slot raise to establish faces. Mining is done in both directions on strike with one face leading the other. Extreme end raises are equipped to serve as access raises for men and material. The lower level is equipped with boxes at set intervals from which ore will be drawn.

PRODUCTION RATES
Concurrent development on 30 Level and 34 Level has been planned. Development from the shaft towards the various orebodies on 30 Level will be done with drill rigs drilling two ends per rig per day, while development on 34 Level will be done conventionally.

LIFE OF MINE PLAN
The Blanket LoM plan commences in 2020. A LoM of seven years from the beginning of 2020 is expected for the Blanket Mine.

The mining strategy targets primarily the Mineral Resources below 750 m Level. Mining in the Lima orebody targets Mineral Resources above 750 m Level. In the ARS East West Limb, Blanket and Blanket Feudal orebodies, some mining will take place above 630 m Level.

Mine Design Criteria for Blanket Mine:
Main Level Spacing - 120m;
Sub-level Spacing (Middling) - 15m;
Drawpoint Crosscut Spacing - 15m;
Diamond Drilling Crosscut Spacing (Along extraction haulage) - 7.5m;
Extraction Haulage Spacing from Orebody - 15m;
Development Lead Angle 45 Degrees;
Production Lead Angle 72 Degrees;
Sill Pillar Thickness - 30m;
Sill Pillar Spacing - 90m.

Following the successful commissioning of the No. 4 Shaft Expansion Project in September 2010, the underground workings have increased production to approximately 1,200 tonnes of ore per day using both long-hole open stoping and underhand stoping methods. Broken ore is trammed along the 22 Level rail system by battery locomotives and the ore cars trains are self-tipped onto one of three grizzlys above the ore bins which are located between 22 Level and the 765m level crushing station. The minus 300 mm rock held in three underground storage bins, Payable ore and waste ore are held in separate storage bins and handled accordingly. Ore is gravity fed from these ore bins onto the 765m Level crushing station conveyor which discharges the ore onto a vibrating grizzly feeder which discharges the oversize into a 30 x 20 Telsmith jaw crusher.

The underground crushing station ensures that all the run-of-mine ore is reduced to minus 150 mm in size as this provides for the optimisation and greater efficiency of the automated skip loading and hoisting operations. This allows mining and hoisting activity to continue without interruption.

Blanket No. 4 Shaft has been equipped with the first automated loading system in Zimbabwe which sequentially fills the two six tonne ore skips which are hoisted from the 789m level to surface.

The double compartment No. 4 Shaft is Blanket’s main shaft for hoisting ore to surface from the loading stations at 510m and 789m below surface, and it has a proven hoisting capacity of 110 tonnes per hour from 789m. The Jethro and Eroica Shafts and the No.5 and No.6 Winzes are used for transporting personnel and materials underground, and the No.2 and Lima Shafts are also used for hoisting ore to surface.

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The Blanket gold plant consists of a conventional crushing, milling, CIL, batch elution and smelting configuration current running at 55 ktpm. The crushing and milling circuits are designed to process RoM. However, the CIL and downstream circuits were designed to treat tailings dam material at a rate of about 110 ktpm (or 3,800 tpd). The CIL is currently used exclusively for treatment of RoM at a rate of up to 55 ktpm.

The plant consists of the following circuits:-
• Primary crushing - jaw crushing
• Secondary crushing - cone crushing in closed circuit with a screen
• Primary Milling - rod mills in open circuit
• Regrind - ball mill in closed circuit with cyclones
• Gravity Concentration – Knelson concentrators and Gemini table
• Intensive leach for gravity concentrate
• Thickening - Dewatering cyclones
• Leaching - Carbon in Leach (CIL)
• Elution and electrowinning – Combined in batch mode
• Casting - smelt house
• Carb ........