Version 1.1.1 is a minor update of Version 1.1 that contains a few
bug fixes that were deemed significant enough to justify an
interim release. This is the version that should be used for bond
calculations in the State of Nevada after November 1, 2006.
When you load the model for the first time, you should see a
security warning dialog box appear. This lets you know that the file
contains macros and give you the option to verify that the code
comes from a publisher with a valid code signing certificate. A code
signing certificate is verified digital signature that ensures that
any code (programs) or macros are published by a person or company
registered with an internet code certifying organization. The code
written for the SRCE was written and signed using this type of
signature to protect users from forged versions that could contain
malicious software code.
The first time you load SRCE model you should see a dialog box looks
like the one above. This gives you an option to review the
certificate and then enable the macros contained in the SRCE. You
must do this for the model to work properly. You can avoid having to
accept the code signature each time you open the program by checking
the box that says "Always trust macros from this publisher".
Cost data is imported into the SRCE model using the "Import Cost Data"
option from the custom SRCE Menu. If the cost data file changes, you
will need to re-load the cost data to update the model.
The data must be in the exact format contained in the user cost
data file (Cost Data USR.xls) file available from the
Downloads page of this web site or a
standardized cost data file available from your local regulatory
agency. Links to some of these regulatory web sites are also listed
on the Downloads page of this web
site.
The standardized versions of the cost data file are locked and
cannot be edited by the user. These files are typically maintained
and updated by regulatory agencies responsible for reviewing and
approving reclamation cost estimates for financial surety purposes.
The cost data cells in the user cost data file are unlocked to allow
users to enter their own cost data (e.g. mine costs).
When you try to load cost data from a data file you see the
following message:
This error message appears when you try to import a cost data file
that is not in the correct format. Because of changes that may occur
from one Model version to the next, the format of the cost data
files may also change.
For use with Version 1.1 or 1.1.1 of the model you need to use a
version 1.4 cost data file. The standardized Nevada cost data
cost_data-std-nv2006.xls can be downloaded at the
NDEP website. For a
user editable version 1.4 cost data file, go to the
Downloads page on this site.
Typically, if the regulatory agency responsible for reviewing and
approving reclamation cost estimates for financial surety purposes
in your area has adopted the Nevada SRCE as an acceptable
reclamation cost estimating method for your area, they should have
an area-specific version of the standardized cost data file
available on their web site.
We will attempt to keep an up-to-date list of links to regulatory
agency websites that contain standardized data files, but contact
your regulatory agency if you do not find a link for your area on
the Downloads page of this web
site. If an agency requests that a copy of the file be stored on
this site you will be able to find it on the
Downloads page of this web site.
If your local regulatory agency has not created a standardized
data file, you can use the user cost data file (Cost Data USR.xls)
file available from the Downloads
page of this web site to input your own cost data into the model.
Cells formatted for user input are colored green, cyan and
yellow. All other cells are locked and cannot be accessed by the
user. The only exception to this are the User sheets, which are
unlocked to allow user input and formatting to all cells except the
headers.
Green cells are formatted for direct input.
Cyan cells contain drop-down lists that allow the user to select
from a list of valid options.
Yellow cells are used for direct user input that overrides
calculated values for earthwork volumes or areas (i.e. regrade
volumes or areas for revegetation).
Where appropriate, data entry tips are provided when a cell is
selected.
Like any computer model, the accuracy of the SRCE is directly
affected by two factors:
To the degree possible, we have attempted to provide references,
figures and footnotes in the model to describe the assumptions and
methods used in the calculations. A technical reference manual that
will further detail the methods is in production.
The input provided by the user will have a significant effect on
the accuracy of any reclamation cost estimate generated by the
model. The basic philosophy used in developing the model assumed
that the user would have a basic working knowledge of reclamation
cost estimation techniques along with an accurate description of the
facilities, a good topographic map of the project and an engineering
scale. The user should be able to generate all of the required input
using these items. Other methods including CAD, GIS, and engineering
software can also be used to prepare the user input data.
The number of scrapers or trucks required to efficiently move cover
material or topsoil is calculated based on the time required to fill
each truck/scraper and the cycle time for each truck/scraper (i.e.
time required for each truck or scraper to make a round trip to/from
the borrow source to the facility to be covered). The number of
trucks or scrapers is then optimized based on the the time required
to load each truck/scraper, a method referred to as
loader-limited or dozer-limited. In other words, the
model assumes that there will always be a truck/scraper ready to be
loaded as soon as the previous one is loaded.
Not yet, but the primary development goal of version 1.1 is the
ability to use either English or metric units. This version is
scheduled for release in March 2006. Keep checking the
What's New page for updates
How was the SRCE model tested?
Testing of the model was performed first by the primary
developers using hypothetical and actual data from real mine sites
(alpha testing). Model results using real mine sites were compared
to other methods. After initial testing, two separate beta test
versions were distributed to state and regulatory agencies, mine
operators, and the public for further testing.
Throughout the alpha and beta testing processes, comments were
compiled and, as necessary, changes were made to the next version of
the model. Version 1.0 represents the first official public release
of the model and is, in effect, the first field trial of the model.
While it would be nice to think that we have found most of the
bugs and thought of most of the features that the model should
include, we are more realistic that that. First of all, there is
already a list of features to be included in future releases. We
will include those as soon as we can get around to it. Second, we
expect the users in the field to think of things we didn't and find
bugs we missed. Basically, we assume that this model will always be
a work in progress.
Rounding. The Nevada SRCE working group determined defined the
criteria for rounding of number in the model. This option in
Microsoft Excel is implemented by using the Round function [Round(number,
n) where n = the number of decimal places]. All calculations in
the model are performed using the default rounding (none) until one
of the a final number is calculated.
For the final numbers used in the model, the working group set
the following rounding criteria:
|
Item |
# of decimal points |
|
lengths (ft or m) |
0 |
|
volumes (ft3, yd3
m3) |
0 |
|
areas (acres, hectares) |
1 |
|
areas (ft2, m2) |
0 |
|
hours |
1 |
|
money ($, other) |
0 |
Example:
When the total hours required to haul
and place cover are calculated, the initial calculations (cycle
times, maneuvering times, etc.) are performed using no rounding.
When these interim calculations are used to calculate the final
number of hours is calculated, the number of hours is rounded to one
decimal point.
When the number of hours is then
used to calculate the labor and equipment costs, the final cost
calculation is rounded to the nearest unit (e.g. dollar).
The model needs to determine surface area (i.e. the area of the
non-planar surface) of a facility to accurately estimate cover and
revegetation areas. A map area (or footprint area) is
the horizontal projection of a facility. Therefore, if a facility
has sloped areas (e.g. a waste rock dump), the actual surface area
will be slightly larger than the horizontal projection, or map area
of a facility. The amount of the difference is determined by the
angle of the sloped portion. The greater the slope angle, the larger
the difference.
In the waste rock dump and heap leach modules, the model asks for
a final footprint area in the user input because it uses that
information along with the horizontal projection (footprint) of the
slope area to determine the amount of flat area in the final
configuration. The footprint of the slope area is not
displayed anywhere in the output.
If you open more than one copy of the model at a time and then
close one, the StdRecCost menu option at the top of the Excel
screen will disappear. To get it back, go to the Macros option on
the Tools menu.
This will open another dialog box that will contain at least two
macro names.
Select MakeBondMenuBar from the macro list and the
StdRecCost menu option should reappear on the Excel menu.
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