(a)(a) How many years will it take to complete mining at this project?

Operating days in the year350days/yearDaily production rate15,000tonnes/dayYearly production rate5,250,000tonnes/yearTotal amount of ore25,000,000tonnes

Time to compete project4.8yearsTime to compete project4years10months

(b)(b) How large will the heap leach pad be (in m2) if the ore is stacked to a height of 25m at side slopes of 18 degrees?Volume of heap leach pad=Volume of pyramid with base (B)h=25m=18=M/V=1.6tonnes/m3V=M/=25,000,000tonnes (total)V=15,625,000m3

Volume of pyramidal frustum V=(h/3) * (2 + 2 + )=h / tanmtan=0.3249197=76.94m

= + 2= - 23V/h=( - 2)2 + 2 + ( - 2)

Rearrange to give:( - 2)2 + 2 + ( - 2) -3V/h = 0Roots of quadratic give:= ( 12 (3V/h - 2)) / 6

2=5920.093V/h=1875000( 12 (3V/h - 2)) =4735.92218733521= + ( 12 (3V/h - 2)) / 61=866m(negative value, ignore)Hence area of pad should be ~=2B=750,411m2

A top= A bottomA sides

(c)(c) An additional cover layer of 1-m thick will be place on the slopes and the top of the heap. Estimate the amount of material that will be used in cubic meters and in tonnes, for the given placed (on the heap) ore density. From part (b)=76.94m=866m= - 2=712.3824615653mArea of top of heapAtop=2Atop=507,488.77m2Area of each side (assume all same)h=83.3333333333mAside=65,776.87m2Total heap surface areaAtotal=770,596.26m2Cover thicknesstcover=1.00mAmount of material to be usedVcover=770,596.26m3Place ore density=1.6tonnes/m3=M/VM=VMass of cover materialmcover=1,232,954.01tonnesUnit cost of placing material$3.25/m3Total cost of placing material$2,504,437.84

A top= A bottomA sides

(d)(d) How large an area is under leach for the given leach application rate and processing flow rate?Leach application rate10L/hr/m2Processing flow rate1,500m3/hrArea under leach150m5/LConvesion for 1m31,000L

Area under leach150000m2

(e)(e) How long does it take to stack enough material 5m high to provide this area under leach (assume vertical side slopes for this calculation)?Surface area under leach150,000m2New height for heap 5mNew heap volume750,000m3Ore density1.6tonnes/m3New tonnage for volume1,200,000tonnesProduction rate15,000tonnes/dayTime to stack material80days

(f)(f) Calculate the spacing of the drain pipes in the drain layer if the maximum saturated zone (h) is 0.5mh = L/2 * (w/k) i.e. L = 2h * (k/w)For given:h0.5mk2.00E-03m/sw1.00E-06m/s

k/w2.00E+03L44.72m