How to Set Up a Processing Plan in MSOPIT’s Economics Panel

Understanding the Panel

You have 5 gradeItems.

We have yourMetal targets butYou may add oneFor value per tonOnce that isComputed intoThe block model

You could also haveThings like a freeMilling gold gradeAnd an encapsulatedGold grade

(your project is simplified to have constant percentagesBy ore type).

Ore Types Ore types goAcross theTop.

The MaterialCode identifiesThe block modelItem containingThe data.

You have a type8 carbonateOre but no type7.

Processes

Processes run downColumns.

You may have a hostOf processes thatMay apply to oneOr more ore types

You may have highCost high recoveryLow cost low recoveryProcesses.

Usually best recoveryIs at the top.

A zero recovery waste process must be last on the list.

Each Cost and Economics SubpanelApplies only to one ore type and process

How do I dealWith ore andOverburdenMining costs?

When you are inA process/ ore typeBox the miningCost is an oreMining cost

When you are inA waste cell theMining cost is forWaste.

(Important note 1- You do not build a stripping ratio into a mining cost)(Important note 2 – Haulage distance and handle costs may differ by location)

What’s this business about haulage and handling costs may vary by location?

• You may blast ore more carefully than waste– This could make ore mining higher cost

• Your waste dump could be further than the mill– This could make haulage costs more for waste– There may also be a placement cost for waste

• You could put this in waste mining cost• Or have a non-zero process cost for waste placement

• You may have a leach with its unique haulage distance• You may have more than 1 mill each with a unique

haulage distance

Now Lets Get a Processing Cost

• It is important to understand that a block of ore will only be assigned to one process.– If you have 5 mills, 2 leaches, and 1 dump, a block

of ore will go only to one of those processes.• Significance will become apparent in the example

My Process

Stuff

High Grade

LeachGrade

WasteGrade

Crush Gravity

FreeMillingGold(95% rec)

FreeMillingSilver(90% rec)

Tails

?

Sulfide

Oxide

3 Stage Float

CopperConcentrate

PyriteConc.

Roast

PIP Leach

Strip/EW

Vat Leach

SX/EW

$1.25/tonne$0.75/tonne

(96% rec)

($4.00/tonne)

($5.25/tonne)(94% rec)

(90% rec)

($0.40/lb)

(99.5% rec)

Copper

($4.50/tonne)

($7/oz)

(92% rec)

($1.25/oz)(97% rec)

Reclaim (0.35/tonne)

Silver Cons(87% rec)

Now Let Me Take Ore Type 3

This is 50% mix of oxide and 2ndary sulfide ore – it is assumed I can partition the block byTruckloads to one process or the other (oxide or sulfide).

Lets look at the oxide track - I reclaim from stockpiles and crush for $1.10/tonne

Next I gravity concentrate – my gold concentrate I get 95% recovery on my gold I get 0.95 * 0.12 recovery on silver in the gold cons 11.4% I get 90% of 76% recovery of silver on my silver cons 68.4% I add $1.25/tonne to my processing – total to this point $2.35/tonne

I go to the VAT leach and recover 96% of my copper (the silver is not recovered)I add $4.00/tonne to the process cost – total to this point $6.35/tonne

Oxide Ore Products and Values

• SX/EW produces finished copper from solutions for 40 cents/lb– My copper to the end of the concentrator process is worth

• $3.25 - $0.40 = $2.85/lb• I get 0.96*0.995 = 95.52%

• My gravity gave me– 95% recovery with gold cons valued at $1,134.3/oz– 11.4 % silver recovery valued at $25/oz * 0.93 = $23.25/oz– 68.4% silver recovery valued at $22.09/oz

So What Do I Get for a Oxide Tonne

• Processing Cost $6.35/tonne• Copper 95.52% recovery valued at $2.85/lb• Gold 95% recovery valued at $1,134.3/oz• Silver– Add up the recoveries 11.4 + 68.4 = 79.8%– Take a weighted average of the values• (11.4*$23.25+68.4*$22.09)/(79.8) = $22.25/oz

Oh But that is Half the Story

• What happened to the sulfide?– It was pulled out of a stockpile and crushed

$1.10/ton– It went to gravity concentration for $1.25/tonne– $2.35/tonne to this point– It still made gold and silver cons but recovery is

different

Gold and Silver Recovery in Gravity on the Sulfides

• Gold is 50% free milling so recovery of gold is– 0.95 * 0.5 = 47.5% valued at $1134.3/oz

• Silver – only 12.5 is going with the gold and only half the gold was free milling– 6.25% * 0.95 = 5.94% valued at $23.25/oz– The silver in sulfides will go on to flotation• There will be no gravity silver concentrate

Our Story Moves to Flotation

• We Have 3 Flotation Stages for $5.25/tonne– Cost to this point $7.60/tonne

• Copper 94% recovery valued at $2.86/lb– (Price per lb for this example is coming from earlier presentation on obtaining the value of metals in concentrate)

• Gold – gold encapsulated in pyrite is recovered by floating the pyrite– 90% of 50% - 0.9*0.5 = 45% recovery– Now we need the value of the gold in that pyrite concentrate

• Silver Sulfides are recovered as a floatation product– 87% recovery of 75% of the contained total– 0.87 * 0.75 = 65.25%– Suppose that the value of silver in sulfide concentrate back calculates

to $19/oz.

Lets Look at the Pyrite Concentrate

• Looking at the ore support 1.36% pyrite has about 0.046 oz per tonne of gold– One tonne of ore would contain

• 2205*0.0136 = 29.98 lbs pyrite (about 30 lbs)• Thus a tonne of pyrite concentrate would have 3.38 oz of gold in it

• The process roasts the pyrite for $4.5/tonne– 4.5/3.38 = $1.33/oz

• We then recover 92% of the gold as relectrowon metal for $1.25/oz– $2.58/0.92 = $2.8/oz off– Thus we have 0.45 * 0.92 = 41.4% gold recover valued at

• $1,200/oz - $2.8 = $1,197.3/oz

Of Course we Have Silver in the Pyrite Concentrate

• 6.25% of the silver is in pyrite concentrate• The silver will be electrowon with about 87%

recovery and costs covered by gold– 0.0625*0.87 = 5.44% valued at $25/oz

• Let us assume that the silver in the copper concentrates goes as a credit to cancel some penalty

So Putting it Together for Sulfide

• Process Cost $7.6/tonne• Copper 94% recovery valued at $2.86/lb• Gold – summing up– 47.5% valued at $1,134.3/oz from gravity– 41.4% valued at $1,197.3/oz float and roast– Total Recovery 88.9%– Weighted average value• (47.5*$1,134.3+41.4*$1197.3)/88.9 = $1,163.64/oz

Continuing On With Silver

• 5.94% silver recovery with gold value $23.25/oz

• 65.24% silver sulfide float valued at $19/oz• 5.44% from electrowin valued at $25/oz• Total 76.62%• Weighted average value– (5.94*23.25+65.24*19+5.44*25)/76.62 =

$19.76/oz

Now Where Are We?

• We know the cost and recovery for oxide ore• We know the cost and recovery for sulfide ore• But our type 3 ore can only go through one

mill process– We are assuming we can separate it by the truck

load– Thus half of each block will go through each

process• For an over-all we can just take the average

Our Average

Oxide• $6.35/tonne

• Copper 95.52 rec at $2.85/lb

• Gold 95% at $1134.3

• Silver 79.8% at $22.25/oz

Sulfide• $7.60/tonne

– (average $6.98/tonne)

• Copper 94% at $2.86/lb– (average 94.76% rec at

$2.855)

• Gold 88.9% at $1,163.64– (average 91.95% rec at

$1148.48)

• Silver 76.62% at $19.76/oz– (average 78.21% at

$21.03/oz)

Thus for the Mill Cell for Ore Type 3

• The processing cost is $6.98/tonne• Copper recovery is 94.76% and copper value is

$2.855/lb in various concentrates• Gold recovery is 91.95% valued at

$1,148.48/oz• Silver recovery is 78.21% valued at $22.03/oz

Disclaimer

• The layout of your process may differ. Your recoveries, costs, and product values may vary– This illustration is intended to show how a result

compatible with MSOPIT can be obtained– It is not intended to suggest that the exact values

shown here can be used in your project.