Principles of Radioactive Waste Management and Disposal.

1. INTRODUCTION

Waste can be defined as any material that will be or has been discarded as being of no further use. While the wastes generated in conventional industries have some associated chemical, physical, biological hazards, the case of radioactive wastes presents a long term challenge on account of the hazards due to radioactive emissions of alpha, beta and/or gamma radiation from the radioactive wastes. Many of the long lived nuclides present in radioactive waste from nuclear plants have half-lives much in excess of human life-times. One of the most radio-toxic elements known to man is Plutonium which is present in very small quantities in wastes generated in reprocessing facilities. Plutonium in its isotopic form of Pu-239 has a half life in excess of 24000 years. This represents generations of human life-times. Hence it becomes the responsibility of the waste generating agency to ensure minimal generation of such long lived waste and implement the best & safest possible disposal options for these wastes.
To get a clear picture about how rad-waste is being managed, it is essential to know the sources of radioactive waste and from which stage of the nuclear fuel cycle they arise from. Each of these stages generates wastes, which contain radionuclides depending on the nature of the operations involved.
In the mining and milling stage, the production of uranium gives rise to radioactive wastes, containing low concentrations of uranium. This waste is mainly contaminates with the daughter products of uranium like Thorium, Radium & Rn.
In the Uranium purification & fuel fabrication stage, purification of yellowcake, conversion to oxide, enrichment and fabrication of fuel elements results in waste streams. At this stage wastes include 'trapping materials from offgas systems', lightly contaminated trash and residue from recycle or recovery operations. These wastes contain Uranium and in case of mixed oxide fuel, Pu is also present.
Reactor operation and power generation stage: Waste streams from nuclear reactors contain fission and activation products. These streams results from the treatment of reactor coolants used in the heat transport and the polishing of spent fuel pool storage water.
The radio active wastes from the treatment of primary coolant systems and offgas treatment system include 'spent ion-exchange resin' and filters as well as some contaminated equipment.
Radio-active waste is also generated in the replacement of activated core components such as control rods, shot-off rods and neutron sources.
In addition to the above, reactor operation generates spent nuclear fuel which is treated as radio-active waste by some countries that do not re-process their fuel.

2. Management of spent fuel:

Spent nuclear fuel contains Uranium, Fission products and actinides (like Pu, Am, Np etc..) Spent nuclear fuel generates significant heat when freshly removed from the reactor. This spent fuel is either considered a waste or reprocessed for recovery of the useful fissile components like U, Pu etc.. ( as India is doing).
During the fuel reprocessing stage, solid radioactive wastes like: fuel element cladding called as 'Hull', and other insoluble residues are generated. These may contain activation products as well as some undissolved fission products, very small quantities of U and Pu.
The principal liquid waste streams generated during fuel reprocessing is the nitric acid raffinate from extraction cycles, which contains fission products and actinides in significantly high concentrations.
Decommissioning of nuclear reactors, fuel reprocessing facilities& other allied facilities: It results in rad-wastes of a large variety. This type of wastes includes: contaminated concrete, structural material, mechanical components, other equipments etc. Though there is a lot of emphasis on the idea of decontaminate and re-use, still many types of solid rad-wastes are un-avoidable. Liquid wastes especially results from DC operation.
Wastes from outside Nuclear power activities: Radioactive wastes are also generated in R&D activities using research reactors, accelerators and radio-isotope production facilities.
Classification or categorization of radio-active wastes: Radioactive wastes can be classified on the basis of a number of considerations:
1. They can be classified as solid, liquid and gaseous waste based on their physical forms
2. as low level, intermediate and high level waste based on the activity content.
3. On the basis of 'what goes where' ie.. on the disposal method adopted.
4. on the basis of 'source of origin' in different phases of the nuclear fuel cycle whether from mining & milling, fuel fabrication wastes, reactor wastes and wastes from spent fuel re-processing.

Table-I Classification of radio-active wastes based on activity-levels and dose rates:

Category	Solid (Surface Dose rate: milliGy/h)	Liquid Activity (Bq/ml)	Gaseous Activity(Bq/ml)
I	< 2 milliGy/h	< 3.7 x 10-2	< 3.7 x 10-6
II	2 - 20 milliGy/h	3.7 x 10-2 to 3.7 x 101	3.7 x 10-6 to 3.7 x 10-2
III	> 20 milliGy/h	3.7 x 101 to 3.7 x 103	>3.7 x 10-2
IV	Alpha bearing	3.7 x 103 to 3.7 x 108	-
V	-	3.7 x 108	-

Table-2: International Classification of radioactive waste

Waste classes	Typical characteristics	Disposal options
1. Exempt waste (EW)	Activity levels at or below regulatory concerns	No radiological restrictions
2. Low and intermediate level waste(LILW)	Activity levels above clearance and thermal power below about 2kW/m3	-
2.1 Short lived waste (LILW-SL)	Restricted long lived radionuclide concentration( limitation of long lived alpha emitting radionuclides to 4000Bq/g in individual waste packages and to an overall average of 400Bq/g per waste packages)	Near surface or geological disposal facility
2.2 Long lived waste(LILW-LL)	Long lived radionuclide concentration exceeding limitations for short lived waste.	Geological disposal facility
3. Hi- level waste	Thermal power above about 2kW/m3 and long-lived radio-nuclide concentration exceeding limitations for short-lived waste.	Geological disposal facility

3. Planning for waste management:

Certain aspects are important in this respect. They are mainly:
(i) establish procedures for minimization, proper segregation, collection, interim storage and transport of radioactive wastes.
(ii) Development of processes for treatment and conditioning for conversion to acceptable waste forms for interim storage for disposal and reduction of volume.
(iii) Define and implement acceptable waste disposal concepts.
(iv) Specific investigations and surveillance programme for disposal sites.

4. Desirable characteristics of waste forms:

Desirable characteristics in waste forms acceptable for disposal are:
(i) Solid form, preferably a rigid monolith of low surface area.
(ii) Low leach rate in water for radio-nuclides of interest
(iii) Good thermal, chemical, mechanical and radiation stability
(iv) Should be compatible with the surrounding medium.

5. General principles of waste management:

The three basic principles /concepts applied to radio-active waste management are:
(i) delay and decay
(ii) dilute and disperse
(iii) concentrate and contain

The first concept is applicable to short-lived wastes.
The second to large volumes of low-level liquid effluents from nuclear installations located on coastal areas or near large water bodies & atmospheric discharge of gaseous waste through tall stacks and subsequent dispersion.
The third concept is the one applied to wastes which cannot be managed on the basis of the first two.

6. Procedure for concentration and conditioning of solid and liquid wastes:

Waste	Process
Compressible solid waste	Baling
Combustible solid waste	Incineration; and fixing the flyash in a suitable media.
Liquid effluents	Evaporation: discharge the condensate as low level effluent; fix the concentrate in a suitable medium as solid waste. Co-precipitation:after adjusting pH etc.. add suitable carriers to precipitate radio-nuclides; filter the slurry; sludge is to be fixed in asuitable media eg: copper ferrocynide for Cs, barium sulphate for strontium. Ion exchange:Sythetic organic ion-exchange materials will concentrate the radio-nuclide from the effluent; on elution a concentrated regenerant waste stream will result which can be subject to a co-precipitation process.. In-organic ion-exchangers such as vermiculite can be used to selectively retain certain radio-nuclides and can be disposed off as solid waste.

7. Management of high level wastes from spent fuel re-processing

In re-processing, the useful Pu & U are extracted from fuel, for conversion into fresh fuel. In this process various wastes are produced containing the fission products and waste actinides as well as active fuel cladding. Almost all the activity, including 0.1- 0.5% of the actinides is concentrated in a small volume of high level liquid waste called 'raffinate' waste.
Initially these acidic liquid wastes are stored in high integrity stainless steel tanks in underground concrete vaults with secondary containment and effective leak detection systems.
Since the activity concentration can be in the range of 5000 - 10,000 Ci/L, considerable heat generation results due to radio-active decay and an effective heat removal system is to be put in place to prevent the solution from boiling.

It is generally recognized that storage in liquid form is only a temporary arrangement to provide operational flexibility and ultimately it has to be converted into a solid. This step of conversion into a solid leads to the following advantages:
a) reduces the mobility of the waste
b) requires less supervision
c) enables the waste to be transported safely for disposal
d) results in reduction of the volume of the waste to be disposed off.

8.Basic solidification processes :

In the vitrification process, process calcine is formed at a temperature of 500 – 600 celcius. Water boils of, nitrates are concerted into oxides. The glass forming ‘frit’ ( mainly borax and silica) is added in the correct ratios and the temp. is raised to 1000 celcius. Upon cooling a glass-like boro-silicate is formed. The selected glasses have proved very resistant to the effects of heat and radiation.

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Google Earth Pro Is Now Free

Image saved from Google Earth Pro.

Google Earth Pro, the premium version of Google's popular Google Earth service, is now free. Unlike standard Google Earth, Google Earth Pro comes with a suite of professional-grade features, like a map-making tool. Measuring tools allow users to quickly calculate distances, both linear and radial, as well as the square footage of custom-outlined areas. For GIS (Geographic Information Systems), the Pro version allows to import .shp files, high resolution images, and other GIS data sets into Google Earth view.

Advantage of Google Earth Pro over non- Pro Version -

• Utilize data layers to locate your target demographic
• Measure area, radius and circumference on the ground
• Use Movie Maker to produce media collateral
• Print high-resolution images for presentations and reports
• Import large vector image files to quickly map GIS data
• Map addresses with the Spreadsheet Importer

Google Earth Pro requires a license key. If you do not have a key, use your email address< and the key GEPFREE to sign in.

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Basic Geological Mapping

Author(s):Richard J. Lisle, Peter Brabham, John W. Barnes

About this Book
Part of The Geological Field Guide Series, Basic Geological Mapping, 5th Edition is an essential basic guide to field techniques in mapping geology. Now completely revised and updated the book retains the concise clarity which has made it an indispensable instant reference in its previous editions. It provides the reader with all the necessary practical information and techniques that they will need while carrying out work in the field, covering a wide spectrum of different conditions, needs and types of countries. This edition covers new developments in technology including Google Earth and the use of GPS. This is an ideal field guide to geological mapping for 2nd/3rd year undergraduates of Geology, Hydrogeology and Geological Engineering.

Contents

Preface to the Fourth Edition ix
Preface to the Fifth Edition xi
1 Introduction 1
1.1 Outline and Approach 1
1.2 Safety 2
1.3 Field Behaviour 4
1.4 A Few Words of Comfort 5
2 Field Equipment 6
2.1 Hammers and Chisels 6
2.2 Compasses and Clinometers 8
2.3 Hand Lenses 13
2.4 Tapes 14
2.5 Map Cases 14
2.6 Field Notebooks 15
2.7 Scales 16
2.8 Protractors 16
2.9 Pencils, Erasers and Mapping Pens 17
2.10 Acid Bottles 18
2.11 Global Positioning System (GPS) and Mobile Phones 19
2.12 Other Instruments 23
2.13 Field Clothing 26
3 Topographic Base Maps 27
3.1 Types of Geological Map 27
3.2 Topographic Base Maps 29
3.3 Geographic Coordinates and Metric Grids 30
3.4 Grid Magnetic Angle 33
3.5 Position Finding on Maps 34
3.6 Use of Air Photography as a Mapping Tool 43
3.7 Suitability of Images for Geological Mapping 48
4 Methods of Geological Mapping 50
4.1 Strategy for the Mapping Programme 50
4.2 Mapping by Following Contacts 51
4.3 Traversing 52
4.4 Exposure Mapping 55
4.5 Mapping in Poorly Exposed Regions 57
4.6 Superficial Deposits 62
4.7 Drilling 66
4.8 Geophysical Aids to Mapping 67
4.9 Large-Scale Maps of Limited Areas 71
4.10 Underground Mapping 74
4.11 Photogeology 76
5 Technological Aids to Mapping 80
5.1 Digital Terrain Models 80
5.2 Topographic Surveying Techniques 86
6 Field Measurements and Techniques 95
6.1 Measuring Strike and Dip of Planar Structures 95
6.2 Plotting Strike and Dip 101
6.3 Recording Strike and Dip 101
6.4 Measuring Linear Features 102
6.5 Folds 105
6.6 Faults 110
6.7 Thrusts 112
6.8 Joints 112
6.9 Unconformities 114
6.10 Map Symbols 114
6.11 Specimen Collecting 116
6.12 Field Photography 118
6.13 Panning 124
7 Mappable Rock Units and Lithology 126
7.1 Lithostratigraphy and Sedimentary Rocks 126
7.2 Sedimentary Formations 127
7.3 Rock Descriptions 128
7.4 Identifying and Naming Rocks in the Field 129
7.5 Fossils 133
7.6 Phaneritic Igneous Rocks 134
7.7 Aphanitic Igneous Rocks 135
7.8 Veins and Pegmatites 135
7.9 Igneous Rocks in General 136
7.10 Pyroclastic Rocks 138
7.11 Metamorphic Rocks 138
7.12 Economic Geology 140
8 Field Maps and Field Notebooks 146
8.1 Field Maps 146
8.2 Field Notebooks 154
9 Fair Copy Maps and Other Illustrations 162
9.1 Fair Copy Maps 162
9.2 Transferring Topography 163
9.3 Transferring Geology 163
9.4 Lettering and Symbols 164
9.5 Formation Letters 165
9.6 Layout 165
9.7 Colouring 167
9.8 Stratigraphic Column 167
9.9 Overlays 168
9.10 Computer Drafting of the Fair Copy Map 169
10 Cross-Sections and 3D Illustrations 171
10.1 Cross-Sections 171
10.2 Method of Apparent Dips 175
10.3 Down-Plunge Projection Method 177
10.4 Balanced Cross-Sections 179
10.5 Columnar Sections 179
10.6 Block Diagrams 180
10.7 Models 183
11 Geological Reports 185
11.1 Preparation 186
11.2 Revising and Editing 186
11.3 Layout 186
11.4 The 'Introduction' 188
11.5 Main Body of the Report 188
11.6 The 'Conclusions' Section 191
11.7 Text Illustrations 191
11.8 References 192
11.9 Appendices 193
11.10 Some Final Thoughts 193
Appendix A: Adjustment of a Closed Compass Traverse 195
Appendix B: Field Equipment Checklist 197
Appendix C: Indicators of Stratigraphical Way-Up 202
Appendix D: Useful Chart and Tables 203
References 205
Index 209

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Fourier Transform Infrared Spectroscopy- Introduction and Priciple

INTRODUCTION

Fourier Transform Infrared Spectroscopy (FTIR) is a technique that is extremely useful for the characterization of Organic materials (including polymers) and certain inorganic compounds. Fourier Transform Infrared Radiation (FTIR) is a type of spectroscopy IR analysis that uses infrared radiation to record molecule movements via computer-based programs. It uses a formula called Fourier Transform and a scheme of conversion called Michelson Interferometer. FTIR is the most recent technology that uses IR in quantitative analysis. It is used by organic chemists to determine the components of organic compounds. Most of the organic compounds reveal their distinguishing component when exposed to infrared radiation. The revealed distinguishing component emits energy (wavelength) that is represented by a graph called spectrum. The spectra obtained by FTIR provide information about the presence of specific molecular structures. The electromagnetic spectrum is composed of energy that may behave both as a particle and as a wave. When we describe this energy as a particle, we use the word photon. When we describe this energy as a wave, we use the terms frequency (ν) and wavelength (λ). Frequency is the number of wave troughs that pass a given point in a second and wavelength is the distance from one crest of a wave to an adjacent crest. Frequency and wavelength are inversely related, according to the equation E = hν = hc / λ. Therefore, as frequency increases, wavelength decreases. When we discuss IR spectroscopy, we introduce a new unit of measurement called the wavenumber (νλ). The wavenumber is the number of waves in one centimeter and has the units of reciprocal centimeters (cm^-1). Since the wavenumber is inversely proportional to wavelength, it is directly proportional to frequency and energy which makes it more convenient to use.

PRINCIPLE

FT-IR stands for Fourier Transform Infrared, the preferred method of infrared spectroscopy. FTIR is based on the fundamental principles of molecular spectroscopy. This broad-ranging area of physics and chemistry covers a multitude of experimental techniques, some of which are found in other oil analysis tests, and others that are so sophisticated that they are of importance only in research laboratories.
The basic principle behind molecular spectroscopy is that specific molecules absorb light energy at specific wavelengths, known as their resonance frequencies. For example, the water molecule resonates around the 3450 wave number (given the symbol cm^-1), in the infrared region of the electromagnetic spectrum.
An FTIR spectrometer works by taking a small quantity of sample and introducing it to the infrared cell, where it is subjected to an infrared light source, which is scanned from 4000 cm^-1 to around 600 cm^-1. The intensity of light transmitted through the sample is measured at each wavenumber allowing the amount of light absorbed by the sample to be determined as the difference between the intensity of light before and after the sample cell.
When IR radiation is passed through a sample, some of the infrared radiation is absorbed by the sample and some of it is passed through (transmitted). The resulting spectrum represents the molecular absorption and transmission, creating a molecular fingerprint of the sample, like a fingerprint no two unique molecular structures produce the same infrared spectrum. This makes infrared spectroscopy useful for several types of analysis. An infrared spectrum represents a fingerprint of a sample with absorption peaks which correspond to the frequencies of vibrations between the bonds of the atoms making up the material.
Because each different material is a unique combination of atoms, no two compounds produce the exact same infrared spectrum. Therefore, infrared spectroscopy can result in a positive identification (qualitative analysis) of every different kind of material. In addition, the size of the peaks in the spectrum is a direct indication of the amount of material present. With modern software algorithms, infrared is an excellent tool for quantitative analysis. To identify a component of certain compounds, they are exposed to high energy such as Infrared Radiation (IR). The reaction results to emission of energy showing the reactions of the molecules, which are automatically plotted to a graph by one of the programs embedded in spectroscopic instruments. Using the generated graph, organic chemists analyse the plot and detect distinctive peaks that can be attributed to the components of the compound.
For instance, a graph shows two distinctive peaks, and after analyzing the plot, one can find out that one peak corresponds to Hydrogen (H) and the other is Oxygen (O₂); thus, we can safely say that it is H₂O or water molecule. Molecules that react with IR always exhibit the same distinguishing peak of energy so they can easily be identified from the graph. In the infrared region of the spectrum, the resonance frequencies of a molecule are due to the presence of molecular functional groups specific to the molecule. A functional group is simply a group of two or more atoms, bonded together in a specific way. In the water molecule (H₂O), it is the O-H functional group that contributes to the resonance frequency around 3450 cm^-1.

The Sample Analysis Process

The normal instrumental process is as follows:
1. The Source: Infrared energy is emitted from a glowing black-body source. This beam passes through an aperture which controls the amount of energy presented to the sample (and, ultimately, to the detector).
2. The Interferometer: The beam enters the interferometer where the “spectral encoding” takes place. The resulting interferogram signal then exits the interferometer.
3. The Sample: The beam enters the sample compartment where it is transmitted through or reflected off of the surface of the sample, depending on the type of analysis being accomplished. This is where specific frequencies of energy, which are uniquely characteristic of the sample, are absorbed.
4. The Detector: The beam finally passes to the detector for final measurement. The detectors used are specially designed to measure the special interferogram signal.
5. The Computer: The measured signal is digitized and sent to the computer where the Fourier transformation takes place. The final infrared spectrum is then presented to the user for interpretation and any further manipulation.

Figure: Block Diagram

Because there needs to be a relative scale for the absorption intensity, a background spectrum must also be measured. This is normally a measurement with no sample in the beam. This can be compared to the measurement with the sample in the beam to determine the “percent transmittance.” This technique results in a spectrum which has all of the instrumental characteristics removed. Thus, all spectral features which are present are strictly due to the sample. A single background measurement can be used for many sample measurements because this spectrum is characteristic of the instrument itself.

Bond Vibrations: The Basis of IR Spectroscopy
Spectroscopy is the study of matter and its interaction with electromagnetic radiation. All matter contains molecules; these molecules have bonds that are continually vibrating and moving around. These bonds can vibrate with stretch motions or bend motions. If we imagine two balls attached by a spring, representing a diatomic molecule, the movement of each ball toward or away from the other ball along the line of the spring represents a stretching vibration. Stretching can either be symmetric or asymmetric. A molecule with three or more atoms can experience a bending vibration, a vibrational mode where the angle between atoms changes.
In the following examples, a triatomic molecule ABC is considered.

Stretching Vibrations-

Symmetric Stretch: allows molecule to move through space.

Asymmetric Stretch: leads to an increase or decrease in bond length .

Bending Vibrations-

Figure: Bending Vibrations.

Each excited vibrational state is reached when a molecule is exposed to a specific frequency. In order for a bond to be promoted to the excited state, it must be exposed to radiation of the exact same frequency as the energy difference between ground and excited states. Determining these frequencies and representing them allows us to determine the bonds that exist in a molecule. These frequencies all lie within the infrared region of the electromagnetic region, a region of lower wavelength than visible light. A machine called an IR Spectrometer passes infrared radiation through a sample of an unknown compound and uses a detector to plot percent transmission of the radiation through the molecule versus the wavenumber of the radiation. A downward peak on the plot represents absorption at a specific wavenumber. In sum, IR spectroscopy is useful in determining chemical structure because energy that corresponds to specific values allows us to identify various functional groups within a molecule. An IR spectrum usually extends from radiation around 4000 cm-1 to 600 cm-1 and can be split into the functional group region and the fingerprint region. The fingerprint region is different for each molecule just like a fingerprint is different for each person. Two different molecules may have similar functional group regions because they have similar functional groups, but they will always have a different fingerprint region.

About the Author

Sukanta Goswami

Guest Author

Sukanta Goswami has done Graduation and Masters from Presidency College, Kolkata in Geology. He is also M. Tech. from Homi Bhabha National Institute, Mumbai. He is working as Scientific officer in Atomic Minerals Directorate for Exploration and Reserch. He is a good sportsman.

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How to create a simple Contour Map in Surfer?

Contour Map is a map that shows lines of equal magnitude (like elevation, concentration, precipitation etc.). Contour map for required parameter (Z) can be plotted with respect to coordinate data (X,Y). Different set of contour maps can be plotted if one has multiple Z values for X, Y coordinates.

Uses of Contour Maps

Contour maps are extremely useful in various fields like Meteorology, Environmental science, Physical Geography and Oceanography, Ecology, Social Sciences, Civil Engineering and Geology. In geology contouring is mostly used in structural geology, sedimentology, stratigraphy and economic geology. One of very common example is topographic map where elevation is used to show topography of area. Another example is Isopach maps to illustrate variations in thickness of geologic units. An example of simple contour map is given below -

In Surfer contour map can be prepared based on a grid file. We have already discussed about grid file creation.

How to create Grid file in Surfer?

If you already well versed with Grid file creation then you can download Demo Grid file for practice.

To create contour map one has to perform following steps:

Step 1: Click the Map ↦ New ↦ Contour Map command, or click the button in the map toolbar. Then Open Grid dialog will be displayed.

Step 2: Select the grid file you created in previous tutorial (Demo Data.grd) by clicking once on its name. The file name is entered in the File name box.

Step 3: Click on Open Button or alternatively Double Click on file name.
Step 4: In the Assign Coordinate System dialog, accept the default Unreferenced local system and click OK. The map is created using the default contour map properties.

 

Step 5: If you wish to save contour map; by default it will be saved in the same directory in which grid file was present with extension .srf.

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How to Create Grid File in Surfer ?

A grid is a series of vertical and horizontal lines that are used to subdivide XY plane into number of blocks. Intersection of vertical and horizontal lines are called Grid Node. Each grid node is represented by a Z value. These rectangular array of Z values are used to generate maps. In Surfer, each grid node is indicated with a "+" in the grid editor window. Each blanked node is indicated with a "x" in the grid node editor. The selected grid node is displayed with a red diamond around the grid node.

To prepare Grid File in Surfer one has to do these five steps.
Step 1: Go to your Desktop or Start Menu click on Surfer icon . Following dialog box will be open by default.

Step 2: Now locate Grid menu in top Menu Bar and click on Data. Alternatively you can also click on Grid icon .


Step 3: After clicking; Open Data dialog box will be opened that is to load the data. If you are in the right directory then simply select data file and click open button. Otherwise use windows explorer to locate your data file and load the data. For tutorial  purpose a data file Demo Data has been prepared.
You can download format of data file from here Download Demo Data File.
 
Step 4: After clicking on Open button Grid Data dialog box will be opened. The Grid Data dialog allows you to control the gridding parameters.

Here you will see following options-

The Data Columns section is used to specify the columns containing the X and Y coordinates, and the Z values in the data file.
The Filter Data button is used to filter your data set.
The View Data button is used to see a worksheet preview of your data.
The Statistics button is used to open a statistics report for your data.
The Grid Report option is used to specify whether to create a statistical report for the data.
The Gridding Method option is used to specify the interpolation gridding method.
The Advanced Options button is used to specify advanced settings for the selected Gridding Method.
The Cross Validate button is used to assess the quality of the gridding method.
The Output Grid File displays the path and file name for the grid file.
The Grid Line Geometry section is used to specify the XY grid limits, grid spacing, and number of grid nodes (also referred to as rows and columns) in the grid file.
The Blank grid outside convex hull of data automatically blanks any locations that are outside the data area.
Click OK. By accepting the defaults, the grid file uses the same path and file name as the data file, but the grid file has a .GRD extension.

Step 5: By default, a Surfer dialog appears after gridding the data with the full path and file name of the grid file that was created. Click OK in the Surfer dialog. The Demo Data.grd grid file is created.


If Grid Report was checked in the Grid Data dialog, a report is displayed. You can minimize or close this report. This report contains detailed information about the gridding process.

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A Breif Introduction to Surfer

About Surfer

Surfer is a grid-based mapping program that interpolates irregularly spaced XYZ data into a regularly spaced grid. Grids may also be imported from other sources. Surfer uses these grid files to produce different types of maps. Different methods of gridding (like Kriging, Nearest Neighbor, Minimum Curvature, Inverse distance to a power and many more ... ) and mapping options are available allowing you to produce the map that best represents your data. In addition, data metrics allow you to gather information about your gridded data in the form of report. The grid files themselves can be edited, combined, filtered, sliced, queried, and mathematically transformed.

What for Surfer can be used ?

Frankly speaking Surfer is one of the best and robust package when it comes in preparation of contour diagram. Surfer basically interpolates a Z data that may be elevation, assay value, stratum thickness, grade etc. spaced in XY plane (e.g. Easting & Northing). The following output can be generated from Surfer.

• A contour diagram for XYZ data.
• Prepare 3-D Wireframe for XYZ data.
• Can create Base Map from XY data.
• Create watershed map types that calculate and display drainage areas and watershed boundaries.
• Create profiles automatically from map layers.
• Can create 3-D Surface map.
• Can create Post map for overlay purpose.
• Shaded Relief Map can be created.
• Can create Grid Vector Map.

Conclusion

Surfer is a powerful and user friendly package for Geology. Here one can play with polyline and polygon. Polyline can be converted in polygon and vice versa. Polygons can be combined together to a single polygon. Data can be imported in Excel, GPX, ASCII, and GRIB formats. It can also import attribute information from files that contain attributes, such as TIF, GPX, or SHP. Files can be exported in Image, PDF, BLN, BNA, GSB, GSI, KML, KMZ, MIF, and SHP file formats. Symbols, texts, scale bar, direction, legend, colour scale etc. can be incorporated to enhance the map presentation.

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