Tuesday, August 28, 2012

Coal: GPT Calculations

From reading GPT Application and doing a little arithmetic, here's some GPT Bulk COAL Calculations: 
[weight in metric tons (mt) = 2205 lbs]

1 gondola car = 102 metric tons [mt]
125 gondola cars = 1 unit train [7000'] - (ultimately to 8500' long trains)
1 unit train = 12,750 mt

East Loop Stockpile = 2.75 to 2.90 million mt [say 3 million mt]
@ 8% of annual throughput: ~3 million mt / 12.750 mt / train = 235 trains to fill stockpile

235 trains / .08 = 2941 trains/year = 100%
2941 trains/year / 365 = 8 trains/day -[coal only]
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Cargo Vessels: Large Bulk Carriers @ 180k dwt to 250k dwt [deadweight tons]

Cd = dwt/ Delta = 0.78 to 0.84 [Revenue Cargo Factor]

Panamax size vessels: 950' X 106' X 39.5' X 190' [Length, Breadth, Draft, Tallest Height]
Ships larger than these qualify as Capesize vessels.

Very Large Ships with 1 screw: speed = 11 to 16.5 knots; long stopping distance; wide turning radius

DWT [Revenue Cargo] Estimates:

250k dwt @ 0.84 load factor: 210k mt / 16.5 trains / 46.7 ship loader hours @10k lb/hr or 4.5 mt/hr

250k dwt @ 0.78 load factor: 195k mt / 15.3 trains / 43.3 ship loader hours
180k dwt @ 0.84 load factor: 151.2k mt / 11.8 trains / 33.6 ship loader hours

180k dwt @ 0.78 load factor: 140.4k mt / 11 trains / 31.2 ship loader hours

Since there are to be 3 berths, each with a dedicated ship loader, up to 3 vessels could be loading at the same time.
GPT estimates 487 vessels per year / 365 = 1.33 vessels per day [average, operating at full capacity]
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