October 8–12, 2012, Dubrovnik (Cavtat) 1

Evaluation of Production and Cost of Komatsu PC200 Excavator during Forest Road Construction in Caspian Forest of Iran

Naghdi Ramin1*, Nikooy Mehrdad2, Bagheri Iraj3, Marzban Shoeyb1

1 Faculty of Natural Resources, University of Guilan, Iran. rnaghdi@guilan.ac.ir; shoeyb.marzban@yahoo.com

2 Faculty of Natural Resources, University of Tehran, Iran. Nikooy@guilan.ac.ir

3 Faculty of Agricultural Sciences, University of Guilan, Iran. irajbagheri@guilan.ac.ir

Abstract:This research was carried out in compartments 52 and 53 of series 7 Shenrood forests (Siyahkal), in order to evaluate production and costs of Komatsu PC 200 excavator. 30 lateral profiles were chosen randomly in different slope classes. With regards to the operation along the roads being carried out at slope of 10 to 70%, three slope classes were considered (10-30, 30-50 and 50-70%). The total operation time of excavator in slope classes of 10-30, 30-50 and 50-70% were 72.89, 73.48 and 77.6 minutes, respectively. The average amount of production in slope classes of 10-30, 30-50 and 50-70% were 17.3, 16.63 and 15.77cubic meter per hour respectively and there were significant effect of slope on volume of cut and fill, volume of earth works and hourly production (cubic meter per hour), but there were no significant effect of aspect slope on hourly production (meter per hour). The cost one cubic meter excavation of earth works were 28650 (2.20$), 29804 (2.29$) and 31429 (2.42$) Rials.

Keywords: Excavator, Hourly production, Forest road, Iran

1 Introduction

During forty years of preparing and implementing the forest plan in northern forests of Iran, over 6000km of forest road have been constructed (Abdullah Pur, and Asadi 2001; Khatibi 2004). Today, a machinery cost is a major cost of forestry project and can affect the profitability of the project. In previous years only the bulldozer machinery has been used for cut and fills operations in the northern forest of the country, but today the focus of forest roads in steep terrain has deployed the idea of sustainable development and protection of natural areas. Since the precision of excavator in road construction is high, therefore the use of excavator is essential.

The excavator consists of a rotating cabin which is situated rubber wheels or tracks and a back hoe is attached to the front end of the excavator. This machine is able to perform activities such as cut and fills, dredging, digging, use of hydraulic hammer to break rocks and stones, uprooting of tree stump, channel construction, excavation, embankment construction for road construction, (Turan 2006).

Time efficiency is the ratio of effective operating time to total operating time (the ratio of the time a machine is effectively operating to the total time the machine is committed to the operation). Excavationmachinery production is equal to length of excavation (m) and volume (cubic meters) per unit time (Abeil1985). Factors affecting excavation machinery production include: slopes, soil depth, density, texture andmoisture and number of stumps and stones in the road and climate conditions, the shape and size of bucket, wear, engine power, driver skills, ergonomics, and distance of soil transfer, weight and type of machinery (Haarlla 1973; Johnsson 1995; Haghiir chehreh ghani and Alipour 2007). Cost per hour of machinery includes the total fixed cost per hour of machine, variable cost, personnel cost (Amini Rauf 2002).

Cabazas (1994) in his research concluded that the production rate of excavator with 128 hp engine power in the underlying silty texture soil and latitudinal slope of 10 and 15% were, 76 and 86 cubic meters per

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hour, respectively and in the underlying clay soil and latitudinal slope of 50% was 106 to 123 cubic meter per hour. Orleans department of natural resources of California, 2003 in their latest comments about the protection and restoration of ecosystems in California concluded that the road construction costs are divided into five categories which include costs of machinery and their management, transportation, finish work, personnel and munitions and these costs were compared with each other. The costs of five categories were the 48.96, 0.66, 8.41, 39.59 and 2.39 percent of total costs, respectively.

Parsakho (2008) studied the production and cost of excavator and the average production rate and cost of one meter length of cut and fill at slope class of 30-70% were 18.19 meter per hour and 8517 rial per meter of excavation, respectively. The present study aims to estimate production and the cost per unit of output of excavator and the main hypothesis is that the excavator is economically suitable for the construction of forest roads.

2 Materials and methods

Study area

The forest roads under study are situated in the Series 7 of Shenrood forest (Siyahkal). The series 7 is a part of watershed forests no 25 and is under the Department of Natural Resources is Siyahkal city. Thearea of the series is 3707 hectares and at 50" 47' 49° longitude and at 30" 55' 36° latitude with the altitude ranging between 700 and 2100 meters and average annual precipitation of 1265 millimeters and general slope aspect of the area is north. The soil texture is clay loam and clay and the main roads of the series is grade 2 (Parsakho, 2008). About 3.1 km of existing roads in parcels 25, 26, 52, 53 are constructed with Komatsu PC200 excavator.

Calculation of the number of transverse profiles

Transverse profiles of samples are specified and based on previous studies or initial inventory of the number of transverse profile. In this study, the appropriate number of samples (transverse profiles) was calculated with regard to t=2 and E%95=±%8 from equation below (Zobeiri, 2005).

n= t2 × (Sx %) 2 / (E %) (1)

Selecting sample of the transverse profiles

Considering the operational areas of the excavator along the road were often in slopes of 10 to 70, therefore the three slope classes were 10-30, 30-50 and 50-70%. Thus, after the numbering the profiles onthe map, the profiles were selected for each slope class (Parsakho 2007). So that 30 samples of transverse profiles were selected for evaluating excavator production.

Time study of excavation operation

A time study is a series of methods that determine the amount of time required to perform work that includes the number of personnel, vehicles or mixed activity. A more accurate diagnosis of fractional properties and also to separate the useful work (effective time) from non-useful work (non-effective or delay time) is necessary and also dividing the work into smaller components and then measuring the time for each component.

In this method after determining the boundaries of each component of the work, the start time of work is recorded and after precise control of work flow start time of each component of the work is recorded. In this study, using a Chronometer (hundredth of a minute accuracy) time cycle is measured with continuous timing (Sarikhani, 2001).

Calculation of excavation works volume on direct routes

Excavation volume is calculated according to the area of excavation, excavation of transverse profiles and the distance between the profiles. If both transverse profiles are adjacent to each other and area of first

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profile section iA , area of second profile section 1iA,and distance between two sections 1, iiL (typically

20 m), then the equation below is used to calculate the average volume of excavation (Nobakht 2002; Narimani 2002; Abeli 2000):

1,1

1,2

ii

iiii L

AAV

(2)

1,1

1,2

ii

iiii L

AAV (1/3) (3)

If one section of excavation is cutting and the other section is filling, then the project line crosses the land at the point of land between these two profiles (crossing point A). In order to calculate the volume between the two sections the crossing point section should be considered zero. Therefore the distance between two separate sections are divided into two and the volume between sections are calculated with the point A. Currently, in most projects average method is used (Nobakht 2002; Narimani 2002; Abeli2000).

Excavator production cost in excavation projects

Cost of machine is calculated based on Austrian (Bureau of production and Business of Forests Organization):

Total fixed costs per hour of effective work TFC/PH (F=0.9):

(D+I+T)/PH = TFC/PH (4)

Total variable costs per hour (TOC):

TOC=MR+FLC (5)

Machine cost per hour of effective work ($ / hour) (MRH/PH):

MRH/PH=TFC/PH+TOC (6)

System costs per hour of effective work:

System cost per hour = MRH/SH +MC+PC (7)

Calculation of excavation production costs

Production cost of the system is the ratio between the hourly cost of the system and the hourly production of machine (Naghdi et al. 2004):

Production cost Rial/m3 = Total cost Rial/hour / Production rate m3/hour (8)

Statistical design

The Kolmogorov-Smirnov test was used to assure a normal distribution of the data in each section. Analysis of variance test (One-way Anova) was used for comparison between treatments in differentslope classes. Tukey test and SPSS17 software were used for statistical analysis to determine the effect of slope on time study of excavation operation and the production volume of excavator in different slope classes.

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3 Results

Time study of excavation

As is indicated in the table 1 in slope class of 10-30 %t the net time, total time and delay time are 60.8, 12.09 and 72.89 minutes and in slope class of 30-50 % are 64.28, 9.2 and 73.48 minutes, respectively.The results of this test showed that there were no significant effects of slope on net time, delay and total time (Tab. 1). Total delay times include defect of tracks and bucket of excavator, oil slip due to the excavator not being serviced in time and lack of sufficient spare parts.

Table 1: Time efficiency of excavator at different slope classes ± standard error

Slop categoriesPure timeSlackTotal time

10-30%70.8 ± 3.612.09 ±1.8672.89 ±4.85

30-50%64.28 ± 2.759.2 ± 1.9873.48 ± 3.32

50-70%68.71 ± 2.48.88 ± 2.2177.6 ± 3.79

13%

87%

effective time delays

Figure1: Percent of total time for excavator

5%

95%

Excavation and embankment log removing , diigging root and rock

Figure 2: Graph of pure work for excavator

6%

21%

73%

Operational delays Mechanical delays Personal delays

Figure 3: Graph of delays for excavator

Evaluation of hourly production and excavation volume of excavator at different slope classes

There were no significant effect of slope on the volume of excavation and hourly production volume(cubic meter per hour), but there were significant effect of slope on hourly production (meter/hour). There was a significant difference between volume of cut and fill in different slope classes at 5% level. There was also a significant between the volumes of the excavation in different slope classes at the 5% level. There was a significant different between hourly production (cubic meter / hour) in different slope classes at the 5% level. There was a significant different between hourly production (meter / hour) in different slope classes at the 5% level.

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Table 2: Hourly production and earth work volume for excavator in different slop categories

Slop categories[%]

Volume of excavation

[m3]

Volume of embankment

[m3]

Earthworks volume

[m3]

Hourly production

[m3/h]

Hourly production

[m/h]

10-3028.18 ± 3.5234.18 ± 4.0462.36 ± 7.5551.33 ± 6.9917.3 ±0.08

30-5047.1 ± 3.2753.5 ± 2.2100.6 ± 4.5582.14 ± 5.7516.63 ± 0.05

50-7071.44 ± 3.2479.22 ± 4.22150.66 ± 7.38116.48 ± 7.9115.77 ± 0.06

Excavator production cost in excavation project

Hourly cost analysis of excavator during useful work of excavation operation project in the study area showed that machine cost (total hourly fixed and variable costs) was 207651 Rials per hour of useful work, the machine cost (total hourly fixed and variable costs) was 170303 Rials per hour of planned workand cost per hour of system (total cost of machine, personnel costs and transport cost) was 495651 Rials per hour of useful work and hourly cost of the system (total machine costs, personnel costs and transportcost ) was 458303 Rials per hour of planned work

Rial/m3 495651/83.31 = 5949 production cost in productive machine hour System

Rial/m 495651 / 16.56 = 29930 machine hourproductiveSystem production cost in

Rial/m3 458303 / 83.31 = 5501 scheduled machine hourSystem production cost in

Rial/m 458303 / 16.56 = 27675 scheduled machine hourSystem production cost in

Rial/m3 207651 / 83.31 = 2492 productive machine hourExcavator production cost in

Rial/ m 207651 / 16.56 = 12539 productive machine hourExcavator production cost in

Rial/m3 170303 / 83.31 = 2044 scheduled machine hourExcavator production cost in

Rial/m hour 170303 / 16.56 = 10283 Excavator production cost in scheduled machine hour

Table 3: Hourly cost of system and excavator track komatsu PC200 (price in 2010)

Total price(Rial):Total fixed cost per SH (Rial): 112046

Salvage value(Rial):215000000Operating hourly cost

Productive Machine Hour (PH):1800Maintenance and Repair cost per PH(Rial):40312

Scheduled Machine Hour(SH):2400Fuel and Lubricant per Hour(Rial):17945

Economic life in years : 20 yearsTotal operating cost(Rial):58275

rate: 12% InterestMachine Rate per PH(Rial/hour):207651

Fixed hourly costMachine Rate per SH(Rial/hour):170303

Average annual investment(Rial):1230875000transport cost(two machine, Rial):48000

Interest rate(Rial):147705000Labor cost (6 person, Rial):240000

Depreciation(Rial):96750000Total contract cost(Rial):7375000

Property tax rate(Rial):24455500Fuel consumption(liter): 20

Total fixed cost per(PH):149394Oil cost per liter:60

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4 Discussion

The results of time study of excavation operation showed that 86.55% of total time is spent on useful work and 13.45% is spent on delays. In the operation area the excavator spent 95.56% of useful work on excavation work and 4.64% on uprooting roots, taking out stump and removing stones. The results of time study of excavation operation showed that 74.25% of total time was spent on useful work and 25.75% spent on personnel, technical and administration delays. Parsakho, 2008 showed that in the operation area the excavator spent 96.63% of useful work on excavation work and 3.37% on uprooting roots, taking out stump and removing stones.

The average excavation productions of excavator Komatsu PC200 in slope class of 10-70% were 83.31m3

per hour and 16.56 meter per hour (Tab. 3). Eriksson and Filisson (1989) estimated average production rate of excavator on forest roads of Sweden to be 7/12 m. IUFRO (1995) in a study on the forests of Sweden investigated the production per hour (meter/hour) of three models of excavators namely Komatsu, Caterpillar and Kublako in different slope classes and concluded that production is inversely related to increase in slopes.

Machine cost per hour of useful work was 207651 Rials and system cost per hour of useful work was495651 Rials.. The system production cost per hour of useful work was 5949 Rials per cubic meter and 29930 Rials per meter. Production cost of excavator per hour of useful work was 2492 Rials per cubic meter and 12539 Rials per meter. Selak (1985), calculated the production cost of Angldouzer in slope in classes 30, 50 and 70% to bet from 2.5 to 3, 3-4 and 4-6 dollars per meter, respectively.In previous years only the bulldozer machinery has been used for cut and fills operations in the northern forest of the country, but today the focus of forest roads in steep terrain has deployed the idea of sustainable development and protection of natural areas. Since the precision of excavator in road construction is high, therefore the use of excavator is essential. Now that the excavator machinery is used a lot in roads construction operations, effort should be made to provide suitable solutions so that the machine performance and environmental effects are kept to optimum level. Therefore paying attention to theseinstructions and rules in road construction is essential for long-term goals. While cost factors should be considered for reducing the cost factors such as soil composition, the main factor for reducing the cost of road construction and very good results in terms of economic.

5 References

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