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Post Break Week 4. Coal Comments for Development. Subsidence Try to produce contours of the amount by which surface areas will subside Try to impose the subsidence on the surface contours to examine new surface contours
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Coal Comments for Development • Subsidence • Try to produce contours of the amount by which surface areas will subside • Try to impose the subsidence on the surface contours to examine new surface contours • What will have to be modified as part of reclamation to provide drainage or control river courses?
Direct Mining Costs • You are developing manning tables • You will know labor and benefit costs • Eventually you will add your support people • These will be case specific quantified costs • (a much better estimate than a cost curve) • Since you have a lump sum mining cost curve you will have to figure out how to combine high quality estimates with low quality. • Might want to see if info-mine cost models provide assumption guidance • This issue will come up again with ground control, ventilation, outby haulage, and water management where specific cost estimates exceed the quality of a cost curve
Coal Preparation • You need to develop those grade recovery curves for your prep plant • You have coal quality as a function of time for run of mine • You will need to see what quality specs you can meet at what recoveries. • You should also see if you have viable contract markets you can use for coals such as #7 and #6 • Unless you have a contract market for #7 your previous analysis coupled with the drop in spot prices will make #7 uneconomic
Dewatering • The problem of high flow rates • It is common to have high initial flow rates that reduce over time • Your flow rate maximums may be valuable in case for knowing what kind of extra pump capacity you may need if you hit something unexpected. • Info bit on Ground Freezing • AMC mining indicates that where one must cut through major water bearing formations the ground needs to be frozen for a year before cutting through • Ground Freezing by Hans L Jasberger was published by Elsiever on Dec. 2, 2012. A chapter deals with costs of freezing plants • There is also a seminar series on Ground Freezing • This is not a routine cost experienced by every mine
More Dewatering • Calculations to date seem to deal with natural mine inflow • They do not deal with the water you will introduce in water sprays and other such equipment needs • You appear to be picking pumps that can deliver 3000 GPM and 360 ft of head • You appear to know about 300 ft of static lift • How do you know what your friction loss is without knowing your pipe size of material?
Metal Clean-Up • Issues to Address • Take the pit drawings and add the road network with colors to those drawings to make sure the roads match-up • There are also problems with pits not being merged into topo in the same drawing that showed the roads • When you push-back to the side what is the size of the push-back (ie – how many meters do you push-back) • Is the push-back sized to be practical for your equipment? • Get detailed MSReserve reports that show grade, and type of other and other relevant calculations
Cost Data Prep • You now have road configurations and crusher locations for each of your mining phases • Make sure you have haulage plans and mining costs for each phase of your mine • Cost for 25 year 30, 35 year, 40 year, 50 year mine out rate • (you had a version of this previously – it just needs checking and adjusting) • Make sure you have processing costs for 25 year, 30, 35, and 40, 50, 60, and 70 year mining rates • You probably already have this • Check to make sure you know where mining cost ends and processing cost begins • Example who pays the cost of the overland conveyor to the mill – mining or processing?
Block Model • Add variables for value per ton • You will need multiple variables for different conditions • Run MSOPIT storing values per ton back into the block model for the cost rates of the following mine/mill lives • Mine 25 Mill 25 • Mine 25 Mill 30 • Mine 25 Mill 35 • Mine 25 Mill 40 • Mine 25 Mill 50 • Mine 30 Mill 30 • Mine 30 Mill 35 • Mine 30 Mill 40 • Mine 30 Mill 50 • Mine 30 Mill 60 • Mine 35 Mill 35 • Mine 35 Mill 40 • Mine 35 Mill 50 • Mine 35 Mill 60 • Mine 35 Mill 70 • Mine 40 Mill 40 • Mine 40 Mill 50 • Mine 40 Mill 60 • Mine 40 Mill 70 • Using Audit – pick a block in the main ore body and show its value under each scenario • Make sure you have the capital costs for each of these configurations • You will be using this data next week in VALP runs
Write Your Hearts Out • This week writing portions of your final report will be your largest effort