interpreting seam data

7/18/2019 Interpreting Seam Data

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Interpreting Seam Data

For Minex v6.0

July 2009



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Introduction

Seam data can be in the form of borehole seam intervals and mapping data stored as stringsand points in the geometry file.

Seam intervals are stored in the .B33 database file separate from the downhole sampling andgeological logging data. They may be interpreted from borehole sampling information andadded to the database at any time. These borehole seam intercepts may be used forreporting, plotting and correlating to form a bore seam model.

Seams or layers that are interpreted are then entered into a list (stored in the .B35 file) whichdefines them in stratigraphic order. These are also assigned flags which define them asCOAL or WASTE material, a default density, a pen number used for graphics display and arelated seam if a relationship exists.

RequirementsFor this tutorial you will need:

• To have a basic understanding of the Minex borehole database with the ability tocreate a new borehole database

• To understand the concept of gridded seam modelling used to model coal seamsin Minex.

The following files are required for this tutorial:

o M5_Project1.B31, M5_Project1.B32 and M5_Project1.B34 boreholedatabase files – the borehole database created in the Tutorial “Creating aNew Borehole Database”.

o M5_Project1_Input_Seam_Intervals.xls

o LITHOLOG.SYM – borehole geological symbols file

o LITHOLOG.DIC – borehole geological dictionary file

o SYMBOLS.PAR – colour and line patterns symbol file

o Coal_Highwall.tif – 3D Sirovision image of highwall geology

ObjectivesFrom this tutorial you will learn to:

• Create a seam/layer sequence (.B35) file• Format the seam interval (.A33) data file• Load and validate the seam interval data• Run a stratigraphic check and correct any errors• Plot borehole data and seam intervals with seam correlation lines on cross section• Import a 3D Sirovision image of a highwall• Digitise seam boundary data using the 3D Sirovision image and store the data in the

geometry file to be used later in seam gridding.



Loading Seam Data into the Borehole Database

Interpreting Seam Data Page 2 of 11

Loading Seam Data into the Borehole DatabaseSeam interval files (known as “pick” files) contain interpreted seam interval data which isstored separately from sample data in a borehole database file with .B33 suffix. Pick filescontain FROM and TO depth intervals, a CLASS number and a SEAM name. The following isan extract from the seam interval spreadsheet supplied

M5_Project1_Input_Seam_Intervals.xls:

BOREID FROM TO CLASS SEAM

1125 16.31 19.56 1 B1

1125 64.83 72.19 1 D

1125 72.47 73.225 1 E1

1125 73.225 73.98 1 E2

1127 25.84 30.94 1 D

1127 31.45 31.86 1 E1

1127 31.86 32.27 1 E2

1128 22.7 28.4 1 D

1128 28.53 29.205 1 E1

1128 29.205 29.88 1 E2

1129 21.85 29.4 1 D

1138 45.09 46.88 1 A1

1138 49.72 51.42 1 A2

1138 78.63 79.21 1 B1U

1138 80.73 82.87 1 B1

1138 83 85 1 C1

1138 86.63 89.75 1 C2

1138 116.21 120.7 1 D1

1138 123.95 124.66 1 D2

1138 127.28 127.575 1 E1

1138 127.575 127.87 1 E2

The CLASS number is set to 1 when preliminary seam intervals are Input. The class numberwill be discussed later.

Before you can load a seam pick file you will need to create a Seam/Layer Sequence List.This list will be stored as the .B35 file i

Creating a Seam/Layer Sequence ListTo create your own seam sequence scroll through the M5_Project1_Input_Seam_Intervals.xlsfile and write down all the seams available in the file (e.g. A1, D, D2 etc) and write them below

in the order they occur in within each borehole:

Top seam _______Seam 2 _______etc

Bottom seam _______

You have now defined a stratigraphic list of seams.

To create a Seam/Layer Sequence List in Minex as a framework for the .B35 file:

1. Go to BoreholeDB | File | Create/Edit Seam Sequence.

2. In the Seam code column enter the seam sequence you obtained from the .A33 textfile. F7 to copy lines.





3. At this stage leave the Father code field is blank. Select Father From Seam box.When you save the list the software will assign the Seam code to the Father code.

4. The Material code field gives the type of material within that seam e.g. COAL,WASTE, ORE etc. All the seams you will be entering are coal seams.

5. In the Density field column give the default density of coal for that seam which is 1.4.

6. Choose colours based on the seam groupings so you can visually differentiatebetween seams of different seam groupings.

7. Set a priority of 1 to all seams. Priority is set for the interpolation phase of the seammodelling. It allows you to set seams with more information to have a greater prioritywhen interpolating seams than those with little data.

8. Leave the Expansion field blank. This field is used by geologists as a tool fordescribing seams or inputting actual seam names.

9. Tick the Create Pick File checkbox. This will create a .B33 file using the seamsequence you have specified.

10. Press Save. You will be asked by the software if you want to delete the seam picksfor the seam(s) you are deleting, Select NO.

11. Go to the Minex Explorer and click on the cross and drill down to the Seam Intervaland Stratigraphic Sequence menu. Under the Stratigraphic sequence you should seeall the seams you just entered in the appropriate stratigraphic sequence.

12. You have just set up the .B35 file which stores all the data relating to stratigraphicorder, default density, colour, priorities and material, of seams. Now Save theborehole database using the File menu by selecting the Save menu then SaveBorehole DB.

Creating the Seam Interval Data Format

Like collar and sample data seam or layer interval data is loaded in the borehole database asa formatted ASCII file.

To import borehole seam/layer interval data as a text file into the borehole database you firstneed to make sure that the file is a column format flat ASCII file and that you have a formatdefinition to describe the column position of the five fixed variables (BOREID, FROM, TO,CLASS and SEAM).

To format seam interval data and the seam interval definition file ready for loading into Minex:

1. In your text editor open Borehole.A33 and SEAMS.SFN from the tutorial dataset.2. In your text editor open M5_Project1.PRN and save it as M5_Project1.A33.





3. Now add an embedded format definition at the top of the seam interval data.

; BOREI D 1 10 0; FROM 11 10 2; TO 21 10 2; CLASS 39 2 0

; SEAM 41 5 0; ; 3456789 123456789 123456789 123456789 1234567891067 45. 805 46. 4 1E21068 24. 69 30. 81 1D1068 30. 99 31. 495 1E11068 31. 495 32 1E21077 48. 52 55. 63 1D1077 55. 92 56. 38 1E11077 56. 38 56. 84 1E21078 28. 48 30. 58 1B11078 39 39. 32 1C1

4. Edit the definition header so that it accurately indexes the seam interval data.5. Save M5_Project1.A33.

Now you have embedded a seam interval definition file into the top of the seam interval datafile you can load this data into Minex.

Loading Seam Interval Data

Now that you have set up the .b35 seam sequence file you can load the seam interval datainto Minex. However you first need to set the Seam Interval File to Read/Write.

1. Highlight Interval under the Borehole Database in the Minex Explorer window. In theProperties window change the Read Only field from True to False.

Now the Seam Interval file is editable you can load your Seam Interval data into the database.



Validating Seam Intervals


2. Choose BoreholeDB > Load > Load Seam/Layer . Select BOREHOLE.A33 from yourworking directory.3. Select Embedded Format File as you have embedded the format definition (*SFN file) intothe seam interval file.4. Select Overwrite Existing Data. This will avoid duplicating data that may already exist in thedatabase. Leave the remaining window settings as they are and press Ok.Importing

Seam/Layer Interval (Pick) Files. The seam load report will be sent to the Output window:

====================Seam Load Repor t====================I gnored bor ehol es wi l l be l i st ed.

I nt erval s l oaded : 361 - Rej ect ed : 0 - Tot al : 361


The process of seam validationchecks each individual borehole and produces a report

which lists the:

• Borehole Processed - those boreholes selected and processed,• Barren Boreholes - those holes which have no seam pick intervals,• Negative Thickness - those holes which, due to error in data entry, have a

seam floor above the seam roof,• Undefined From/To - where a seam name (ID) has been input, but where

the seam roof and/or floor depth has not been defined,• Missing Seams in Whole Borehole - lists the seams from the Stratigraphic

Sequence which have not been defined in the seam pick for a borehole,• Missing Seams inside known Borehole - lists the seams which have not

been defined between known picks for a borehole., and• Missing Seams outside known Intervals - lists the seams which have not

been defined above the uppermost known seam pick as well as below thelowermost known seam pick for a borehole.

The report obtained from this process will change as further Bore Seam Modelling processesare performed. Therefore, it is recommended that validation should be checked on a regularbasis.

Run the Seam Validation report and correct any errors

Access the Seam Validation report menu from the BoreholeDB > Reporting menu.

FIGURE 3.4 Seam validation report shows errors in the seam interval file. Note hole C78

The Seam Validation report displays in the Output window as follows:

Barr en borehol es- - - - - - - - - - - - - - - -





Borehol e 1130 has no seams def i nedBorehol e 1174 has no seams def i nedBorehol e 3001 has no seams def i nedBorehol e 3002 has no seams def i nedBorehol e 3005 has no seams def i nedBorehol e 3007 has no seams def i nedBorehol e 3008 has no seams def i ned

Borehol e P67A has no seams def i nedBorehol e V18 has no seams def i ned

Negat i ve t hi ckness- - - - - - - - - - - - - - - - - -

Seam C1 i n Borehol e C78 has negat i ve t hi ckness

Negat i ve i nt erbur den t hi ckness- - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

Undef i ned FROM or TO Vari abl es:- - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

St r ati gr aphi c Check- - - - - - - - - - - - - - - - - - -

St r ati gr aphi c check was successf ul - no er r or f ound.

You should now check out the seam interval for seam C1 in borehole C78 and determine howto edit it.





Plotting seam correlation l ines on borehole cross sections

Use the section S1-2500 you use in the Tutorial “Loading Sample Data into the BoreholeDatabase”. Turn on the Plot Seam/layer IDs and Plot Correlation Lines in the ID’s tab of theBorehole Section Plotting menu.



Collecting and Storing Seam Mapping Data



Most seam mapping data is collected as surveyed seam roof and floor strings from exposedgeology on highwalls or on the wall and roof of underground openings. In most opencut minesthe seam roof boundary is typically cleaner and better exposed than seam floor boundaries.These strings are typically collected by the mine surveyor and stored in the geometry file in amap name such as SEAM. Each string and point is assigned an identifier which conforms tothe naming conventions for seam grids – B2SF for example would be used for structure floordata for seam B2.

Using 3D Sirovis ion Images to Input Seam Data

Sirovision, an innovative software program developed by the CSIRO in Australia, uses digitalcameras and terrestrial photogrammetry to produce accurately surveyed 3D images ofhighwalls which can be directly input and used in Minex. Once displayed in the 3D designwindow, you can digitise seam boundaries on the 3D surface using the photographic imagedetail.

Importing and Displaying a 3D Sirovision Image

Import the Sirovision image file Highwall.tiff using menu File | Import | Import SirovisionModel. Select the image file Coal_Highwall.tif and then press the Ok button to import.

Figure 3.7 Sirovision Import menu allows you to import a 3D Sirovision image and display it inthe 3D Design window

Figure 3.8Display of a 3D Sirovision image in the 3D Design window





To view the image in the 3D Design window you may have to delete other objects and resetthe 3D area.

Digiti sing Seam Boundaries on a 3D Sirovision Image

Whether you are digitising seam boundaries on Sirovision images or importing boundary

strings picked up by a mine surveyor, it is important that you store the strings in the geometryfile in such a way as to use them easily for gridding. It is recommended that you store allseam mapping data in the one map eg. SEAMS and that you name each string according tothe seam name it will be used to create ie. Seam name plus SR for roof, SF for floor and STfor thickness.

Figure 3.9To digitise the seam roof boundary on the Sirovision 3D image make sure you will store theresulting string in the map name SEAMS and the appropriate ident name (seam name plusSR). Each imported Sirovision creates a triangle surface and it is this triangle surface that you willuse to digitise seam boundaries. Make sure then that you are in “Snap to point” mode beforeyou start digitising and that you have selected the appropriate map (SEAMS) and ident name(MT1SR). You will not recognise the seam name MT1 as this Sirovision image is from adifferent dataset – we are just using it to illustrate the method.

Figure 3.10To digitise the seam roof boundary on the Sirovision 3D image make sure are in the “Snap tosolid” mode and select Structure Disc as the data type.



Summary


SummaryYou should now be familiar with the way seam intervals are loaded and stored in the boreholedatabase. You have learned how to:

• Create a seam/layer sequence (.B35) file• Format the seam interval (.A33) data file• Load and validate the seam interval data• Run a stratigraphic check and correct any errors• Plot borehole data and seam intervals with seam correlation lines on cross section.• Digitise seam boundary data using a 3D Sirovision image and store the data in the

geometry file to be used later in seam gridding.

interpreting seam data

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