Combining slash bundling with in-woods grinding operations

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easier to handle, and increases the average weight per cycle, thus improving productivity of loading and hauling stages while reducing their production costs. However, the bottleneck in this system appears to be the bundling stage, with a low production rate production compared to the next stage of loading. Decoupling the bundling stage may reduce the potential system bottleneck by creating a buffer of bundles to be loaded and hauled, thus maximizing a loaders utilization rate. Support costs are often an overlooked component of forest operations. Fuel trucks are needed to deliver and fuel to existing machinery, water trucks are required for dust abatement purposes, and service trucks have the tools and parts necessary for daily maintenance and repairs. The support cost ($14.48/BDT) in this system is the third largest component of total system cost, this includes the cost of owning all of the support vehicles and their assumed use of 30 minutes daily divided by the total tons produced during the operation 280.7 BDT. System supports costs may be greatly reduced if the operation were to be full scale, by increasing the total tons produced. Table 7: Estimated system production and cost. Bundling Loading Hauling Grinding Support Total ¹ Hourly Cost ($/PMH) ² $ 133.19 $126.60 $103.84 $595.71 $57.88 $1,017.22 Hourly Production (GT/PMH) ⁴ $ 10.62 55.88 14.68 46.65 N/A Cost ($/GT) ³ $ 12.55 $2.27 $7.07 $12.77 $10.29 $44.94 Cost ($/BDT) $ 16.20 $2.99 $9.34 $17.97 $14.48 $60.98 Moisture content for bundling was 22.55%, 24.27% in loading and hauling, and 28.95% during grinding. ¹ Total system cost does not include move in costs, transportation to market, or profit allowance. ² ⁴ PMH: productive machine hour ³ GT: green ton BDT: bone dry ton Hauling the bundles to the centralized grinding site cost $9.34/BDT the second lowest component of system cost. Hauling costs represented approximately 15% of the total production cost, but proved to be highly variable depending on road conditions. Sensitivity analysis indicates minimizing road types such as single lane dirt roads which have traveling speeds of less than 10 mph greatly improves trucking productivity and reduces production costs (Fig. 5). Holding all other variables of system cost constant, every mile increase of dirt road hauling distance will cause a $3.07/BDT increase in total system cost. Due to the variability in transportation costs and the high costs associated with hauling on forest roads, it suggested that a harvest site should be located no more than 5 miles away from the centralized grinding site.
System cost ($/BDT) 78.00 76.00 74.00 72.00 70.00 68.00 66.00 64.00 62.00 60.00 1 1.5 2 2.5 3 3.5 4 Dirt road miles 1⁰ gravel road miles 1 2 3 Figure 5: Sensitivity analysis of system production cost on various transportation distances. One factor that had an effect on the overall system cost was diesel fuel prices which were at a national peak during the study in the summer of 2008. Diesel fuel price assumed for the operation was $4.60/gal. Six months later fuel prices in the region dropped to $2.50/gal. Holding all other variables of system cost constant, every dollar reduction of fuel price represents around a $3.52/BDT reduction in overall system cost (Fig. 6). Production Cost ($/BDT) 64 62 60 58 56 54 52 50 2.00 2.25 2.50 2.75 3.00 3.25 3.50 3.75 4.00 4.25 4.50 4.75 5.00 Diesel Fuel Price ($/gal) Figure 6: Sensitivity analysis on system production cost with various fuel market prices.
Page 1 and 2: 2009 Council on Forest Engineering
Page 3 and 4: Pile Class 1 = Mixed size material,
Page 5 and 6: Time study data was collected to ca
Page 7 and 8: Grappling the bundles and compactin
Page 9: The delay-free trucking cycle took
Page 13 and 14: Literature Cited Alcorn, M.W.2008.

Combining slash bundling with in-woods grinding operations

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