In my previous post you can read about SimSched DBS which is a different algorithm in mine optimization. Now I want to show you step-by-step with my new SimSched DBS tutorial and you’ll see how easy to run a project and creating scenarios.
Step-By-Step Mine Optimization
You need block model that has parameters like coordinates, density, grade etc. But you have to consider that your open pit should has rectangular base. I mean, convert your ore to a solid as in the design of pit then just create a rectangular base which enclosing the ore. Then create a pit which has 90 degrees slope and a single bench and then combine it with the topography as shown in the picture below.
Remember that you will not design pit with benches and slope angles. SimSched DBS will do it automatically. Ore and Waste block must be together. So you can use inverse distance weighted block model method or others then easily report to excel.
|Selling Price ($)||250|
|Selling Cost ($)||100|
|Processing Cost ($/t)||2.0|
|Mining Cost ($/t)||0.5|
|Discount Rate (%)||10|
Recovery: is your plant’s ore recovery percentage
Selling Price: Ore sell price
Selling Cost: This is final cost of your mine and all the costs are in it
Processing Cost: is the cost to process a ton of ore
Mining Cost: is operation cost for pit
Once you get the block report, you can start the process.
Your block model must have X,Y and Z coordinates. Next step will be converting the coordinates to the indices. SimSched use integer coordinate system so your indices must be integer.
It is important that the system coordinates from which point of the blocks. Some programs can give you coordinates from bottom corner of the blocks and some other gives from center of the block. In such a case you need to know whether the coordinate is at the corner or at the center.
If theye are not in the center then you shoul use following formula to setup coordinates to the center.
One other important point is that OX,OY,OZ is the your block model’s origin and all converting steps use this origin point to calculate indices. we can think of the origin point as the lower left corner of the coordinate system so to find the origin use the following excel formula:
ie if your coordinates are in A2:1000 cells in the excel then you shoul type the formula +min(A2:A1000) do the same for OY and OZ. This find minimum coordinate point of your blocks.
Now you can convert your coordinates to the indices. For this use the following formula:
The best way to ensure everything is fine is using the following formulas:Matheus Ulhoa
1. Default formula from our tutorial: IX = (X + Dx/2 – Ox)/ Dx, where X, DX, IX refer to the blocks’ centroid, and Ox refers to the block vertice.
2. Adapted version: IX = (X + Dx – Ox)/ Dx to consider every parcel of the equation refers to the blocks’ centroid coordinates.
3. For case , in case you define Ox = min(X coordinates), adapt it to Ox = min(X coordinates) – Dx/2.
Ore Tonnes and Block Tones
For Block Tonnes use the following formula:
Block Tonnes= DX x DY x DZ x Density (t/m3)
For Ore Tonnes use the following formula:
Ore Tonnes= Block Tonnes x Ore Grade (%)
It’s time to calculate the Economic Value Process and Economic Value Waste:
In SimSched’s example there are 2 ore tpye: Cu (Copper) and Au (Gold) so if you work one type of ore you can use the following formula:
Economic Value Process = (Ore tonne x Recovery x (Selling Price – Selling Cost)) – (Block Tonne x (Processing Cost + Mining Cost))
Economic Value Waste = – Block Tonne x Mining Cost
Behind the mine optimization: what’s the idea of this?
Economic Value Process: The ration of these calculations, we multiply our recovery with the ore tone we obtain, and we find out how many tons of ore to achive from the run-of-mine ore. Then we subtract the total cost from the selling price and we calculate our per-ton price.
We can also find out how much we will earn by multiplying the amount of ore achived for sale with our profit. We then multiply the block tones by the resulting operational costs.
So, we multiply by the operational cost that goes up to the processing plus processing plant. Because within a block, besides the ore, there are other invaluable rocks and it is not possible to select it from the block cube during the operation. This block is sent to the processing plant and the ore is taken from it.
If we continue, we will find the economic value of our block by subtracting the value of this second account from the value we calculated first.
Economic Value Waste: during the operation in pit of course there will be waste material that we must move to waste dump area. But since it is not a valuable ore, we only need to apply operational cost to it. It must be negative because there is no gain from this material and it is only cost.
If you’re done then you’re ready to import your csv file to SimSched DBS.
Important: Remember, your indices must be integer and if your indices have floating numbers then you can round up with excel formula. And your csv file must be comma seperation.
Now we’ve following parameters to be imported to SimSched DBS.
Let’s import our data to SimSched
Run SimSched DBS, Double Click MiningMath and Click Run Algorithm.
Click Import Model
Select your csv file and click Next
Your project’s min and max parameters will be shown like this and click Next.
Your table titles will appear here with the state you saved in excel. I’ve typed Cr2O3 for Chromite’s grade so I’ve to select Grade from Field Type.
Wait, be careful!
Enter your block sizes to the Block Dimensions and select your Grade unit from Variables and Click Scheduling.
I’ve put 10x10x10 sizes and selected the % for my chromite ore.
In the General tab enter the Densities, Discount Rate (%) and Slope angles (degrees).
Densities is default value for blocks which have no defined densites. I’ve select %10 Discount Rate and 45 degrees of slope angles for my pit. Normally you can select discount rate 10-12%.
In the Destinations tab you must add Economic Value Process and Economic Value Waste by clicking Add Process, Add Dump. Then enter Recovery value for Economic Value Process because blocks will go to processing. Leave recovery zero for Economic Value Waste because it will go to the waste dump.
In the Production tab enter your Process 1 value. This is the value which will be processed per year. So we can call it facility capacity per year.
In the Geometric tab we must define our operational parameters in the pit.
For more information about widths you can check here.
In the Overview tab you can see all parameters you’ve already entered in Scheduling screen.
Click Run and progress will be started.
When the progress has finished your excel report will be open. You can easly check your datas and table related to the your project.
In SimSched DBS you can see your project with periods and blocks.
If you click the Period, you can see your periods as min and max in below Colormap tab. As you can see my project has 9 years period and if I enter 2 in the Min textbox I can see the period through year 2 to 9 by coloring the blocks to blue.
Write your scenario, read your future.
So, as you can see you can easyly setup and run your mine optimization project in SimSched DBS. In project setup screen (where you entered your parameter i.e. density, slope angles etc.) you can change your values and try different mine optimizations scenarios thus you will have chance to compare it. This will give you to see which scenario data is optimal and profitable for your pit, what NPV will your company achive with this mine optimization.
With SimSched DBS in mine optimization you can also use Blending Tab to determine a block scheduling by the minimum/maximum grade or periods which you want. Also you can use the Other tab for changing periods. In the Geometric tab you can resrict or force your pit by your mine optimization parameter.
Screenshots of periods. From 1 to 9 years…
If you want to learn more about what is SimSched DBS you can visit website and youtube channel clicking here.