Combining slash bundling with in-woods grinding operations

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Figure 2: John Deere 1490D energy wood harvester which produces the bundles, and hook-lift truck used to haul bundles. Dirt road 0.92 miles Unit A 2⁰ Gravel road 0.68 miles Unit B 1⁰ Gravel road 1.64 miles Unit C Centralized grinding site Figure 3: Operation layout map with corresponding road segments. Data collection and analysis Hourly machine costs (Table 2) measured in dollars per scheduled machine hour (SMH) were calculated using standard machine rate calculation method (Miyata 1980). For each machine in the system purchase price, insurance and tax rates, repair costs, fuel consumption, and labor costs were obtained from the contractor, diesel fuel price receipts were averaged throughout length of the operation ($4.60/gal). All machinery were assumed to work 1800 SMH annually and have an economic life of ten years except for the grinder which was 5 year economic life due to associated wear, and the bundler which was assumed to work 2100 SMH as suggested by John Deere Company.
Time study data was collected to calculate hourly production (bone dry ton (BDT)/productive machine hour (PMH)) using standard time study techniques for each element in a machines operation cycle by stop watch (Olsen et al. 1998). A bundling cycle includes traveling to the slash pile, followed by multiple grapples and swings of slash to the in-feed table, and ended when the bundle produced was cut free from the machine. A loading cycle started from traveling to a bundle, followed by swinging empty to the bundle, grappling the bundle, swinging loaded back to the container, and ended by compacting bundle into the container. A hook-lift trucking cycle includes traveling empty to the harvest unit, positioning the truck for loading, loading a container filled with bundles, traveling loaded to the centralized grinding site, and unloading/dumping the bundles. Three types of delay time, including operational delays, mechanical delays and personal delays, were recorded. Regression models for delay-free cycle time were developed using the pre-identified independent variables associated with each cycle. The collected time study data were screened for normality and outliers using histograms and residual plots, and were used to develop predictive equations by running multiple regressions using ordinary least squares estimators, performed in R 2.4.1 statistical software program (R 2006). The final predictive models only include variables that were statistically significant (p-value
Page 1 and 2: 2009 Council on Forest Engineering
Page 3: Pile Class 1 = Mixed size material,
Page 7 and 8: Grappling the bundles and compactin
Page 9 and 10: The delay-free trucking cycle took
Page 11 and 12: System cost ($/BDT) 78.00 76.00 74.
Page 13 and 14: Literature Cited Alcorn, M.W.2008.

Combining slash bundling with in-woods grinding operations

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