The Optimum Slash Pile Size for Grinding Operations: Grapple Excavator and Horizontal Grinder Operations Model Based on a Sierra Nevada, California Survey

Shohei Kameyama,Takuyuki Yoshioka,Bruce Hartsough,Rin Sakurai,Koki Inoue

doi:10.3390/f8110442

Shohei Kameyama, Takuyuki Yoshioka + Show 3 more

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https://doi.org/10.3390/f8110442

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Abstract

The processing of woody biomass waste piles for use as fuel instead of burning them was investigated. At each landing of slash pile location, a 132 kW grapple excavator was used to transfer the waste piles into a 522 kW horizontal grinder. Economies of scale could be expected when grinding a larger pile, although the efficiency of the loading operation might be diminished. Here, three piles were ground and the operations were time-studied: Small (20 m long × 15 m wide × 4 m high), Medium (30 × 24 × 4 m), and Large (35 × 30 × 4 m) piles. Grinding the Medium pile was found to be the most productive at 30.65 bone dry tons per productive machine hour without delay (BDT/PMH0), thereby suggesting that there might be an optimum size of slash pile for a grinding operation. Modeling of the excavator and grinder operations was also examined, and the constructed simulation model was observed to well-replicate the actual operations. Based on the modeling, the productivity of grinding at a landing area of 710 m2 of slash pile location was estimated to be 31.24 BDT/PMH0, which was the most productive rate.

Highlights

Fierce wildfires are currently one of the most severe problems in the westernUnited States
(928 green tonsthat (GT)) of forest slash from the Blodgett Forest Research Station (BFRS) were collected, processed, and transported by Brushbusters for energy use to the Buena Vista Biomass Power (BVBP) facility. This comprised a total of 37 separate chip van loads, with each delivery averaging 16.3 bone dry tons (BDT) (25.1 GT)
Theoretical formula of each element operation time was determined from σ, respectively; the theoretical formula was expected to follow a lognormal distribution the according to distribution of the histogram of the monitored element operation time, and each operation time was the study by Sakurai et al

Summary

Introduction

Fierce wildfires are currently one of the most severe problems in the westernUnited States. California is experiencing one of the state’s worst droughts of the past century. After a century of fire suppression, California’s forests are denser and have fewer large trees. From the 1930s to the 2000s, the number of large trees in the Sierra Nevada mountain range in California decreased by half while the density of small trees doubled [1]. Severe fires are increasing in frequency and size throughout the Sierra Nevada, and regeneration is not a given for severely burned forests where seed trees have been killed across large areas [2]. Fuel reduction operations (e.g., prescribed fire, mechanical treatment, mechanical treatment + prescribed fire) are effective to reduce the risk of high-intensity wildfires and return forests to a more fire-resilient landscape [3]

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