Week 6

1. Week 6

2. Coal Miners • Presentation due on Tuesday following SME trip

3. Big Negotiations • After looking at numbers the company’s land department did some serious negotiating • Clearly the gravy is in the #2 coal and anything that delays it costs more than Iits worth (NPV wise) • The land department pointed out the #7 coal had only a $4/ton profit margin if longwall works in the geometry • The land owners will accept a payment of $25,000,000 per year for 8 years and will waive requirements for mining the #7 coal • From a company standpoint delaying mining #2 costs at least $25,000,000 per year off of NPV

4. More Negotiations • The land department pointed out that discontinuities in the #2 coal seam made parts of the coal not minable by longwall • They showed your map and the large unmined areas • Ok they did not mention that longwall and room and pillar might be used together. • The landowners agreed that if room and pillar with pillar recovery could get more coal than your previous longwall arrangement then they would accept room and pillar in #2

5. New Mandates for Management • You must start mining the #2 coal immediately and you must do so in a manner that does not make #6 and #5 unminable • If this means room and pillar #2 you need to demonstrate you can get more coal with R+P with pillar extraction than your longwall layout (your longwall layout left unmined area so this is likely doable) • You will need to be in the #6, #5, and #2 coal at the same time and keep your mining staged so your seam interactions are controlled • You know #6 is R+P • You know #5 is longwall • You know #2 could be either R+P or longwall depending on over-all recovery and the mandate to do 3 seam mining.

6. Layout and Timing • Do a room and pillar layout with the #2 coal • Calculate your pillar sizing and opening width • Demonstrate they are justified from a rock mechanics standpoint • When pillar recovery is included how many minable tons of coal do you get? • Is the tonnage greater than your first layout for room and pillar only?

7. Produce a Mine Layout and Timing • Create a first draft mine layout for all 3 coal seams • Put timing on the coal mine map to show how you will keep one seam ahead of the other even with mining in all 3 seams being mined at once • Are their areas that due to limited innerburden simply cannot be made to work with all 3 seams • What areas? • Why? • While you do need to do general layout and timing for #5, you do not have to do exact pillar sizing at this time.

8. Coal Preparation • While no one knows exact out of seam dilution it does not take a genius to know that a cut by a 61 inch head will be at least 61 inches high or that a decision to mine 6 foot high in a 4 foot coal seam will cause out of seam dilution or that a decision to cut out 1 foot of clay floor will result in out of seam dilution • Estimate minimum out of seam dilutions

9. Out of Seam Dilution • Consultants confirm that gray shale less than 2 feet thick in #5 and #6 will fall out before it can be bolted (experience of other mines in the area) • It often falls when under 2.5 ft (but this is a minimum dilution estimate) • You have determined to cut clay floor • Include that in minimum out of seam dilution • Any time coal seam height in #6 plus underclay thickness is less than 6 ft (and the top is not nearly certain to fall in) include the cutting needed to get to 6 ft height as part of minimum dilution • Any time the longwall cuts coal less than 61 inches (plus a reasonable guess at additional height for movement) include the additional cut as out of seam dilution for #5

10. Map Minimum Out of Seam Dilution • Do not just take an average • Using 5% dilution contours map out the minimum amount of out of seam dilution in areas of your #6 and #5 coal seams • If you have mining equipment and assumptions for #2 coal mining include those calculations too.

11. Look at How Out of Seam Dilution Impacts Preparation • General assumptions to use • Clay (such as from a floor) will follow water in your coarse and mid size circuits • Clay can be separated partially in flotation and on spirals • Cut roof such a limestone or black shale or sandstone will size similar to the coal but have a specific gravity around 2. Such cut roof will usually be liberated from the coal • Roof fall chunks and slabs will degrade with 20% turning into clay. The rest will be harder and larger than the coal and could be removed in devices such as Bradford breakers.

12. Decision Needed • You will mine #6 and #5 coal at the same time • Both seams have high and low sulfur areas • Will you blend any coals? • Will you try to produce a low sulfur product? • Do you have to use just one seam to meet a specific contract • This might happen if you had a chlorine restriction since #6 is low chlorine and #5 is high chlorine • This might also happen with a real tight sulfur specification.

13. For Each Coal Product • For each product you will produce (by blending or dedicated seam) • Look at what the highest out of seam dilution could be • Predict the quality of your product • Draw out the mass balance as the coal moves through your preparation plant • Look at the lowest out of seam dilution • Predict the quality of the product • Draw out the mass balance as the coal moves through your preparation plant

14. Drawing Details • Draw the layout (floor plan) of your shops, offices, wash houses, warehouses, preparation plant, security stations, and coal loadout • Produce Drawing details of your slope

15. Writing • I don’t believe I have the revision of all the previous write-ups turned in yet. • Get that done.

16. Metal Group • Mini- presentation on Wednesday next week • Working on road (Idris) • Recommend getting a new copy of the file (likely corruption in yours) • Starting where the road was appointed to exit the pit and ending at the waste dump • Create a road centerline going from the start to the destination • Use the querry tool on the polyline (it will get you the X, Y, and Z coordinates of the end points of the polyline) • Using this information calculate the percent grade on each polyline segment • Show an example calculation of how you got the percent grade • Present a table showing the grade on each segment of your route center-line • Do the same for the road to the leach dump • Do the same for the road to be followed by the conveyor from the edge of the pit to the edge of the property covered by topo

17. Create Your Cut and Fill Templates • Determine your road width (it might be different for the conveyor route if you will have a conveyor and service road) • Example – a service road may for a conveyor must have room for the conveyor, but may not have two way traffic for large haul trucks • Allow your cuts to be 42 degrees and your fill to be 30 degrees unless space or other considerations require different assumptions • Show the cut and fill templates you will use in the template editor

18. Attach the Cut Template to the Polyline • Show the undisturbed topo surface and the attached cut template in the same view • Point out where the template is cutting the surface • Do the same for a fill template • Show where you had to make adaptations if you ran into problem areas

19. Create a new Geometry Object for the Road with the Surface • Use the surface intersect tool • Use the fill option to raise the topography in the old surface to the level of the road template • Use the cut option to lower the old surface to the level of the road cut template • Show the finished topo with the road imprinted into place

20. Create two geometry objects – one for cut and one for fill • Use the intersect surfaces and create solids option • Using your fill template and your old surface create a fill solid • Using your cut template and your old surface create a cut surface • Turning off everything else, show these two solids one at a time • Show how you can tell you have a solid • Show how you can tell the solid does not fold onto itself like a moibis strip • Querry the solids and show the cut and fill amount for the roads.

21. Report on your recommendation for the roads • Are you satisfied with the road leading in a direct manner without excessive winding to their destination • Are cut and fill quantities reasonable and well balanced • If things are not satisfactory what do you believe needs to be done to improve things.

22. Fun for Eric • You have selected a location for the dump but capacity is not well matched to your requirements • Using the pit expansion tool create a dump surface that includes and roads and benches you will have in your design • Use the intersect surfaces tool • Create a post fill surface in a new geometry object • Create a fill solid in a new geometry object between the original surface and the finished dump surface • Querry the solid • Keep working on your dump until its volume is within 5% of the required volume

23. Reving Up for the Leach Dump • You already have polyline for the required area for your leach • Try an elevation and location that you think will provide balanced cut and fill • Create a cut surface that projects up from your polyline • Present a view that shows where the cut projection cuts up to the old topo surface • Create a fill surface that projects down from the level of your polyline to the surface below • Present a view that shows where the fill projects down to the old surface

24. Use Your Intersect Surfaces Tool • Create a new geometry object for the surface once the area for the leach pad is prepared • Present views of that prepared pad surface • Create a cut solid for the cut difference between the original and prepared surface • Create a fill solid for the fill difference between the original and prepared surface • Show and querry the solid surfaces • Keep working till cut and fill balance to within 10%

25. Fun for Paul • It has been determined that in-pit crushing and conveying will be used • Adjust your mining cost to reflect material being removed by trucks with transfer to in pit crushing and conveying • The mining cost should reflect drilling and blasting • Loading and truck haulage from benches to the crushing point • Initial crushing in the inpit crusher • Overland conveying to the process mill

26. Adjust Mining Costs for Mining Rate • How is the Mining Cost Different for • A 20 year mining rate • A 30 year mining rate • A 40 year mining rate • A 50 year mining rate • A 60 year mining rate • A 70 year mining rate • How much does your mining cost increase each time you go down a bench?

27. Adjust Processing Costs • For the mill material is already delivered with preliminary crushing to the mill • Show what costs you are including in your milling cost • If you are doing any rehandling in and out of stock piles and not feeding directly in from the mine be sure to include these costs • Show what the cost per ton is for each milling rate • Explain what is making it change with size of the operation.

28. Adjust Other Processing Costs • Your leach processing cost may have plusses and minuses • You avoid crushing and conveying charges • But you must incur longer trucking costs to drive the material out of the pit • Is the difference between these costs a positive or negative number • It may well cost more to haul material to the leach than to haul it to the mill • Now add in the cost of crushing you do before leaching • Add in rehandle costs (the trucks from the mine may be dumping by the leach crusher – with crushing – and then reloading onto trucks again to drive it into place) • Add in any costs for chemicals, solution circulation, collection • How do these costs very with your mining rate?

29. Adjust Your Dump Cost • You probably have assumed your process cost for the dump is 0 but it might not be • Your mining cost included (now) inpit crushing and then conveying to the mill • Obviously this cost is avoided for dump material • But dump material has to be trucked out of the pit to the dump lifts • What does that cost • The difference between these costs can cause a non-zero waste processing cost • Is your waste processing cost positive or negative? • How does it change with your mining rate? • How does it change by bench?

30. Grade Item Adjustments • When you run VALP you will need value per ton to be a grade item • MineSight only allows 5 grade items • You have 5 metals • Silver is an impurity in the gold and follows the gold through the process • Create a new grade item eqau • How many ounces of gold is one ounce of silver equal to in value • Use the user calc function in compass to calculate the eqau • Ieequa = au + ratio*ag

31. Run MSOPIT for the adjusted conditions • Use a mining rate for a 40 year mine life • Having mining and processing costs set for this rate • Use adjustable costs by bench • If your not sure how to do this use the MineSight help function • Use your expected prices (not your high or low) • Get the ultimate pit saving the value per ton back into the block model

32. Provide Pretty Illustrations • Use various 3D and 2D cross sectional views • Set Up a model view on value per ton • What is the range of values per ton for blocks in your pit? • Set the color scheme to display this range effectively • Show 2D cross sections that display the value per ton and the line representing the ultimate pit • (These results will help set VALP next week)