Sunday, 24 September 2017

A COMPUTER PROGRAM FOR COST CALCULATIONS

6/8. PACE - A COMPUTER PROGRAM FOR COST CALCULATIONS

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6.1 Introduction
6.2 Starting PACE
6.3 Machine Rate Calculations
6.4 Road Construction Calculations
6.5 Production and Unit Cost
6.6 Sensitivity Analysis
6.7 Installing the PACE Program


6.1 Introduction
The computer program, PACE (Production and Cost Evaluation), was developed to assist in calculating machine rates, road construction costs, and harvesting costs. It can be used to evaluate tradeoffs between road costs and harvesting costs. This section will describe the PACE program and can be used as a user guide. A computer disk with the PACE program for IBM PC/XT/AT and compatibles are provided with this manual. See Section 6.7 for installation instructions.
PACE is divided into three parts: (1) machine rate calculations, (2) road construction calculations, and (3) harvesting production and unit cost calculations. Analysis begins with the preparation of machine rates for combinations of equipment and labor which will be used in road construction and harvesting. Next, road construction costs are developed using the machine rates from (1). And last, machine rates, road costs, and harvesting production rates are combined to develop production and unit cost estimates (Figure 6.1).

Figure 6.1 Information flow for PACE program.




PACE is easily learned through a tutorial example. The tutorial includes calculation of a machine rate, a road construction cost, and a harvesting production and cost estimate Copies of the computer monitor displays are included along with the formulas used to make the calculations.

6.2 Starting PACE
PACE consists of six programs linked together by an executive program with the main menu. Type PACE and press <enter>. The monitor will display the main menu (Figure 6.2). You are now ready to begin.

6.3 Machine Rate Calculations
Let's begin by preparing a machine rate for an operator with a power saw. To reach the machine rate program menu (Figure 6.3), use the cursor control arrows to highlight the machine rate program, MAC-COST.EXE and press <enter>. The MAC-COST menu (Figure 6.3) will appear.
Follow the key strokes below to enter the data and refer to the formulas in Table 6.1 to understand how PACE is making the calculation.

Key stroke
Explanation
1
Branches to equipment ownership cost screen (Figure 6.4).
550
Type in 550 and either press <enter> or press the down arrow key to enter the data and move to the next line.
...
[continue with input as shown in Figure 6.4]
<esc>
Returns to the main menu of the machine cost program.

Table 6.1 Machine Rate Ownership Cost Formulas
Row
Description
1
Delivered equipment cost
2
Line and rigging cost
3
Tire or track replacement cost
4
Residual value
5
Equipment life
6
Days equipment works per year
7
Hours equipment works per day
8
Interest rate
9
Blank
10
Tax, lic, insur, storage rate
11
Depreciable value
12
Annual depreciation
13
Average annual investment
14
Annual interest expense
15
Annual cost tax, lic, insur, storage
16
Annual ownership cost
17
Annual hours utilization
18
Hourly ownership cost
Rows (1) - (10) are input data.
Row (11) = Row (1) - Row (4)
Row (12) = Row (11) / Row (5)
Row (13) = [Row (1) - Row (4)] [Row (5) +1] / [2 * Row (5)] + Row (4)
Row (14) = Row (8) * Row (13) / 100
Row (15) = Row (10) * Row (13) / 100
Row (16) = Row (12) + Row (14) + Row (15)
Row (17) = Row (6) * Row (7)
Row (18) = Row (16) / Row (17)

Key stroke
Explanation
2
Selects the operating cost screen.
100
Enter the operating costs as shown in Figure 6.5.
...
[continue with input as shown in Figure 6.5]
<esc>
Returns to the main menu.

Table 6.2 Machine Rate Operating Cost Formulas
Row
Description
1
Repairs as % of equip depreciation
2
Fuel consumption rate
3
Fuel cost
4
Lubricants as % of fuel consumption
5
Cost of oil and lubricants
6
Cost of lines
7
Life of lines
8
Cost of rigging
9
Life of rigging
10
Cost of tires or tracks
11
Life of tires or tracks
12
Hourly cost of repairs and maint
13
Hourly cost of fuel
14
Hourly cost of oil and lubricants
15
Hourly cost of lines
16
Hourly cost of rigging
17
Hourly cost of tires or tracks
18
Hourly total operating cost
Rows (1) - (11) are input data.
Row (12) = Row (1) * Row (12)1 / Row (17)1 / 100
Row (13) = Row (2) / Row (3)
Row (14) = Row (2) * Row (4) * Row (5) / 100
Row (15) = Row (6) / Row (7)
Row (16) = Row (8) / Row (9)
Row (17) = Row (10) / Row (11)
Row (18) = Row (12) + Row (13) + Row (14) + Row (15) + Row (16) + Row (17)
------------------
1 Refers to row numbers and values from table 6.1.

Key stroke
Explanation
3
Selects the labor cost screen.
1.10
Enter the labor costs as shown in Figure 6.6
...
[continue with input as shown in Figure 6.6]
<esc>
Returns to the main menu.

Table 6.3 Machine Rate Labor Cost Formulas
Row
Description
1
Base wage for 1st crew position
2
Base wage for 2nd crew position
3
Base wage for 3rd crew position
4
Base wage for 4th crew position
5
Base wage for 5th crew position
6
Base wage for 6th crew position
7
Fringe benefits
8
Non-machine operating hours per day
9
Machine operating hours per day
10
Supervision as % of direct labor
11
Total number of workers
12
Hourly crew wage
13
Hourly direct labor cost per machine operating hour
14
Hourly supervision cost per machine operating hour
15
Hourly total labor cost per machine operating hour
16
Hourly operating cost (equip + labor) per machine operating hour
Rows (1) - (10) are input data.
Row (11) = Sum of workers
Row (12) = Row (1) + Row (2) + Row (3) + Row (4) + Row (5) + Row (6)
Row (13) = Row (12) * [ 1 + Row (7) / 100 ] * [ Row (8) + Row (9) ] / Row (9)
Row (14) = Row (13) * Row (10) / 100
Row (15) = Row (13) + Row (14)
Row (16) = Row (15) + Row (18)1
------------------
1 Refers to Row (18) from Table 6.2.

Key stroke
Explanation
4
Selects the summary cost screen. This screen should appear as Figure 6.7.
Displays the summary of the ownership, operating, and labor costs on the monitor. The equipment description appears at the top of the summary sheet. This was added using option 7 from Figure 6.3.
<esc>
Returns to main menu.

Key stroke
Explanation
6
Selects the save-data option.
70CCSAW
Enter file name. Name must not be more than 8 characters with no decimal point.
Stores the information from screens 1, 2, 3, and 4 to the disk.
We have now completed all information for the machine rate example. Let's try some other options.
5
Displays all machine rate files which have been made with the MAC-COST program and stored on disk. This option is used to recall files.
Note an extension .MAC has been assigned by the program for use in later file manipulations.
To load a file, highlight the desired file using the cursor control arrows and press <enter>. The file will be loaded and the program returns to the main menu.
8
Erases the information currently on the 1, 2, 3, and 4 screens.
9
Returns to the executive program. (Figure 6.2)
This completes the machine cost file preparation. Machine rates for trucks and animals are prepared similarly. The logic is identical with only slightly different questions being asked which are specific to the machine/labor combination being evaluated. Remember, the machine rates are the basic building blocks of any cost analysis and should represent the labor and cost combinations which you will use in later programs. A machine rate could a machine without crew, a machine with crew or a crew without machine. Typical applications might be a power saw with operator, a tractor with operator and helpers, a survey crew with pickup, etc.

6.4 Road Construction Calculations
To prepare a road construction cost estimate for a typical road section we use the CONST.EXE program. The objective of the Road Construction Program (CONST.EXE) is to allow you to develop road construction costs for typical sections of roads or typical road standards. The road costs can then be used in the UNIT.EXE program to develop stump-to-mill harvesting costs and to evaluate the sensitivity of harvesting costs to road spacing alternatives. The CONST.EXE program allows you to specify which equipment/labor combinations you will use for road construction and retrieves the files from your disk. You then estimate the production rates for the equipment/labor combinations for each road construction activity (Figure 6.8). An example follows.

Key stroke
Explanation
PACE
Loads executive program. The screen output should look as Figure 6.2. This assumes that you have not yet loaded the program. If the executive program is still in memory, then skip this step and highlight the CONST.EXE program and press <enter>. The Road Construction Menu should appear as shown in Figure 6.8.
R
Branches to load machine rates for road construction calculations.

Key stroke
Explanation
H
Switches to manual machine selection mode. You can identify a maximum of 12 machine rates. Use the cursor to highlight the desired machine rate file and press the space bar. You will see a "#" sign appear to the left of the file name to indicate it has been selected. Repeat until you have identified the 5 machine rate files shown in Figure 6.9. Then, press <return> to begin loading the files.
Alternatively, you could automatically select the first 12 machine rate files on your data disk for use as machine/labor combinations for road construction by pressing [A].
Next, select the road construction activity you want to evaluate. Let's start with surveying.
1
Branches to the survey window. This should appear as Figure 6.10.
200
Move the cursor to the equipment/labor combination you want and enter the production rate. The activity totals will appear in the lower box.
<esc>
Escape returns to the menu.
Alternatively, you can press <pg dn> or <pg up> to move through the other construction activity screens.
Repeat this procedure for road construction activities 2 through 7.
Skip any activities you do not need.
At any time you can view the road cost summary sheet by pressing <esc> to return to the menu and entering (8).
An example of a summary screen is in Figure 6.11. If you move the cursor to highlight any activity, the equipment mix for that activity is indicated by arrows to the left of the appropriate equipment/labor combinations in the lower window.
<esc>
Returns to the main menu.

Key stroke
Explanation
7
Branches to the landings menu (Figure 6.12). The results from this menu do not appear in the road cost summary. The cost for landing construction however, will be used in the UNIT.EXE program. It is saved along with the road costs when you select the save mode.
<esc>
Returns to the main menu.

Key stroke
Explanation
S
Selects the save data mode. The save data mode has three purposes. First, it provides data for Production and Unit Cost program (UNIT.EXE); second, it provides a way of updating road cost estimates, and third, it is an easy way to create costs for other road standards by modifying production rates in existing files.
Y
Indicates you want to continue with the save option. If you do not want to do this, press <N>.
Low-std
File name under which the data is to be saved.

6.5 Production and Unit Cost
Harvesting production and unit costs are calculated in the UNIT.EXE program. An example of the UNIT.EXE program follows using sample files from the disk.
Key stroke
Explanation
PACE
Loads executive program. The screen output should look as Figure 6.2. This assumes that you have not yet loaded the program. If the executive program is still in memory, then skip this step and select the UNIT.EXE program. (Figure 6.13)

Key stroke
Explanation
R
Reads all machine rates and road costs on the disk. A maximum number of 40 machine rates and 10 road standard files (.RCS) which can be considered at one time.
The machine rates to be used in calculating the felling, yarding, loading, transport, and the road cost are now entered. This is done in two steps: (1) use the tab key to highlight the harvesting activity and (2) use the cursor control arrows to highlight the appropriate machine rate or road construction rate and press <enter>. Select the machine rates and road standard shown in Figure 6.14.
C
Press <C> when you have completed selection of the machine files for the harvesting activities and the road file for the road standard.

Key stroke
Explanation
1
Selects the felling production and cost window (Figure 6.15).
Note the machine costs already appear from the previous step. Complete the information by using the cursor arrow to identify the location, enter the data and then move the cursor to the next data entry location.

Table 6.4 Falling and Bucking Screen Formulas
Row
Description
1
Machine Cost (.MAC, .AML, or .TRK file)
2
Machine minutes to fell and buck tree
3
Volume per tree
4
Delay time (minutes per hour that machine is working, but not doing planned work)
5a
Felling and bucking production per machine hour
5b
Ownership part of felling and bucking unit cost
5c
Operating part of felling and bucking unit cost
5d
Labor part of felling and bucking unit cost
5e
Total unit cost for felling and bucking
Rows (1) - (4) are input data.
Row (5a) = Row (3) * [ 60 - Row (4) ] / Row (2)
Row (5b) = Row (18)a / Row (5a)
Row (5c) = Row (18)b / Row (5a)
Row (5d) = Row (15)c / Row (5a)
Row (5e) = Row (5b) + Row (5c) + Row (5d)
------------------
a Refers to Row (18) of Table 6.1
b Refers to Row (18) of Table 6.2
c Refers to Row (15) of Table 6.3

Key stroke
Explanation
The hourly production adjusted for operating delays and unit costs are shown on the lower screen.
<esc>
Returns to menu or you can move to the next screen by using the <pg dn> key.
2
Complete the skidding activity screen similarly using the test data in Figure 6.16.
The skidding production and costs will not appear until after the road and landing data window has been completed because the road spacing information is needed and is not available at this point.

Table 6.5 Skidding Screen Formulas
Row
Description
1
Machine cost (.MAC, .AML, or .TRK file)
2
Move-in time (machine time landing to landing)
3
Volume per cycle (trip)
4
Outhaul velocity (empty)
5
Lateral outhaul velocity
6
Hook time
7
Lateral inhaul velocity
8
Inhaul velocity (loaded)
9
Unhook time
10
Delay time (machine time the equipment is involved in working delays, i.e. meter is running)
11
Not applicable
12a
Skidding production per machine hour
12b
Ownership part of skidding unit cost
12c
Operating part of skidding unit cost
12d
Labor part of skidding unit cost
12e
Total unit cost for skidding
Rows (1) - (10) are input data.
Row (12a)a = (Volume per landing) / (Trips × Effec Cycle Time / 60 + Move-in)
Row (12b) = Row (18)b / Row (12a)
Row (12c) = Row (18)c / Row (12a)
Row (12d) = Row (15)d / Row (12a)
Row (12e) = Row (12b) + Row (12c) + Row (12d)
------------------
a Volume per landing calculated from information in the Roads / Landings screen. Trips is equal to volume per landing divided by volume per trip.
b Refers to Row (18) of Table 6.1
c Refers to Row (18) of Table 6.2
d Refers to Row (15) of Table 6.3
L-shaped Skidding Pattern
If Row (5) and Row (7) are not zero then calculations are for lateral skidding to a corridor, and then skidding along the corridor to the landing
Cycle Time = [ K * D1 / Row (4) + .25 * D2 / Row (5) + Row (6) + K * D1 / Row (7) + .25 * D2 / Row (8) + Row (9) ] * W
where
K = 0.5 / Row (6) from Table 6.8
D1 = Row (2) from Table 6.8
D2 = Row (3) from Table 6.8
W = Row (5) from Table 6.8
Radial Skidding Pattern
If Row (5) and Row (7) are zero then calculations are for radial skidding to a central landing. The average skidding distance is approximately,
AYD = { .333 * SQR [ (F*D1) * (F*D1) + (D2) * (D2) ] + .333 * SQR [ (.5*F*D1) * (.5*F*D1) + (.5*D2) * (.5*D2) ] } * W
where
F = 1.0 / Row (6) from Table 6.8
D1 = Row (2) from Table 6.8
D2 = Row (3) from Table 6.8
W = Row (5) from Table 6.8
Cycle Time = AYD / Row (4) + Row (6) + AYD / Row (8) + Row (9)
Effective Cycle Time = Cycle Time × 60 / [60 - Row (10)]

Key stroke
Explanation
If lateral inhaul and lateral outhaul are left as zero the timber is assumed to be skidded to a central landing by the shortest path. This can be adjusted by using a weave factor in the Roads/Landing screen. Using the <pg dn> key, go to the roads/landing screen to look at the data needed.
Complete the other screens shown in Figures 6.17 through 6.19.

Table 6.6 Loading Screen Formulas
Row
Description
1
Machine cost (.MAC, .AML, or .TRK file)
2
Machine minutes per cycle
3
Volume per grapple (or other) load
4
Delay time (minutes per hour that machine is working, but not loading, i.e. sorting)
5-6
Not applicable
7a
Loading production per machine hour
7b
Ownership part of loading unit cost
7c
Operating part of loading unit cost
7d
Labor part of loading unit cost
7e
Total unit cost for loading
Rows (1) - (4) are input data.
Row (7a) = Row (3) * [ 60 - Row (4) ] / Row (2)
Row (7b) = Row (18)a / Row (7a)
Row (7c) = Row (18)b / Row (7a)
Row (7d) = Row (15)c / Row (7a)
Row (7e) = Row (7b) + Row (7c) + Row (7d)
------------------
a Refers to Row (18) of Table 6.1
b Refers to Row (18) of Table 6.2
c Refers to Row (15) of Table 6.3



Key stroke

Explanation
<esc>
Returns to the menu.
S
Selects the save mode if you want to keep the parameters and results of this analysis.
Study-1
Creates a file (Study-1 .UCD) for later recall using the (L) option.
Q
Quit. Returns to main menu.
<esc>
Leaves the PACE program.


Table 6.7 Truck Transport Screen Formulas

Row
Description
1
Truck cost (.TRK file)
2
Distance (one way)
3
Volume per truck load
4
Speed unloaded
5
Loading time
6
Speed loaded
7
Unloading time
8-10
Not applicable
11a
Truck transport per machine hour
11b
Ownership part of truck transport unit cost
11c
Operating part of truck transport unit cost
11d
Labor part of truck transport unit cost
11e
Total unit cost for truck transport
Rows (1) - (7) are input data.
Row (11a) = Row (3) * 60 / [Row (2) / Row (4) + Row (5) + Row (2) / Row (6) + Row (7)
Row (11b) = Row (18)a / Row (11a)
Row (11c) = Row (18)b { Row (3) * 60 / [Row (2) / Row (4) + Row (2) / Row (6) ] }
Row (11d) = Row (15)c / Row (11a)
Row (11e) = Row (11b) + Row (11e) + Row (11d)
------------------
a Refers to Row (18) of Table 6.1
b Refers to Row (18) of Table 6.2
c Refers to Row (15) of Table 6.3


6.6 Sensitivity Analysis

The sensitivity of production and costs to changes in the skidding or road cost variables can be examined at any time by paging to the appropriate screen and changing the data. If the machine rate or road standard is changed in this way, the percentage in ownership, operating, and labor remains the same with the new rate. To change to a different machine rate or road file, return to the menu <esc> and read the new machine rate files (R). Then, use the cursor and tab keys as before. The UNIT.EXE program will read the new cost files and your other data will still be available. Remember to save your Unit Cost file before you exit the UNIT.EXE program.


Table 6.8 Roads/Landings Screen Formulas

Row
Description
1
Road cost (.RCS file)
2
Road spacing
3
Landing spacing
4
Harvest removal per unit area
5
Skidding weave factor
6
One way or two way skidding factor
7
Cost per landing
8
Near optimal road spacing
9
Near optimal landing spacing
10-14
Not applicable
15a
Not applicable
15b
Ownership part of road unit cost
15c
Operating part of road unit cost
15d
Labor part of road unit cost
15e
Total unit cost for roads/landings
Rows (1) - (7) are input data.
Rows (8) and (9) are calculated using calculus and / or numerical approximation techniques beyond the scope of this manual. You can verify their goodness by substituting the values displayed in Row (8) and Row (9) into Row (2) and Row (3) and observing the change in TOTAL COST, Row (15e).
Row (15b) = [ Row (1)a * Row (3) / 1000 + Row (7) ] / [ Row (4) * Row (2) * Row (3) / 10000 ]
Row (15c) = [ Row (1)b * Row (3) / 1000 + Row (7) ] / [ Row (4) * Row (2) * Row (3) / 10000 ]
Row (15d) = [ Row (1)c * Row (3) / 1000 + Row (7) ] / [ Row (4) * Row (2) * Row (3) / 10000 ]
Row (15e) = Row (15b) + Row (15c) + Row (15d)
------------------
a Ownership component of Row (1) from (.RCS) file.
b Operating component of Row (1) from (.RCS) file.
c Labor component of Row (1) from (.RCS) file.


The near optimal road and landing spacing is shown on the Road/Landings screen (Figure 6.19). To find the cost associated with this road and landing spacing, enter the road spacing and landing spacing indicated. The results are shown in Figure 6.20. A reduction of $0.17 per cubic meter is achieved by reducing the road spacing to 459 m and the landing spacing to 250 meters. Although the road cost increases to $1.39 per cubic meter, the reduced skidding cost more than compensates for this increase.
The UNIT.EXE program is not designed to have zero landing spacing. A default value of 10 meters is used. If you want to analyze continuous landings, the default value of 10 meters will not appreciably increase the skidding distance or affect the unit costs.

6.7 Installing the PACE Program

The PACE program is designed to reside in a directory of your hard disk. Create a subdirectory on your hard disk and copy the PACE program disk contents into it. Also copy any example data files into the same subdirectory as the PACE program.
When the PACE program loads data files or saves data files, it will always do so to the subdirectory that the PACE program is in. The Delete Utility on the PACE Master Menu can be used to erase files that you no longer want.

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