Creating a 3D model would isolate optimal zones for total reserves of economically extractable gold in mining industry, the groundwater contamination flow from waste infiltrated in environmental case, etc. - Rockware.com
4. Introduction
How to determine the subsurface of Banda Aceh City ?
No directional survey
• Geophysics
• Geological Map Cross-Section
Directional survey
• Civil Engineering (Boring)
• Well Exploration
• Pit Testing for mineral exploration
10. We need :
• Data collection (e.g. Geophysics, Geology, Mining, Geotechnical, Environment)
• That data must have X, Y, Z (spatial) and others value of main parameter
• Computer and Software ( Ex: Rockworks and ArcGIS)
• Basics and advanced concept about Geostatistics
• Lithology and Stratigraphy knowledge for a Geoscientist
12. • The Distribution of Soils/Rocks vertically or horizontally
• Visualization such as : cross-section, fence diagrams, block diagrams
• Calculation of Volumetrics
Important : Creating a 3D model would isolate optimal zones for total reserves of
economically extractable gold in mining industry, the groundwater contamination
flow from waste infiltrated in environmental case, etc.
13. Data Management X : 10.000 (mU)
Y : 12.000 (mT)
Z : 15 (m dpl)
Total Depth of Dowhole : 120 m
Other Information Borehole data
16. Lithology versus Stratigraphy
• Lithology : rocks description based on that characteristics (Jackson, 1985)
• Rock classification into 4 types : Igneous, Sedimentary, Metamorphic, and
Pyroclastics
17. • Viewed into a tab : listing depth to depth, and rock or material type
Rock typeIn the Field Depth to Depth (m)
Lithology versus Stratigraphy
18. • Often repeating others depth
Location 1 Location 2 Location 3
Tab Correlation
Lithology versus Stratigraphy
19. • Stratigraphy : rock layers and stratification based on lithology, environment and
depositional age
• Sub-Fields into 3 types : Lithostratigraphy, Biostratigraphy, Chronostratigraphy
Lithology versus Stratigraphy
LithostratigraphyandChronostratigraphy
Biostratigraphy and Chronostratigraphy
21. • Never repeat others depth
Tab Correlation
Lithology versus Stratigraphy
22. Modelling
• 2D/3D-Modelling is depend upon the number of independent variables
• In a two-dimensional array, the dependent variable (z) is a function of the horizontal
(x,y) coordinates. Also referred to as a “GRID MODEL”
23. Modelling
• In a three-dimensional array, the dependent variable(g) is a function of the horizontal
(x,y) and vertical coordinates (z). Also referred to as a “SOLID MODEL”
24. Geostastistics Basics
• 2D Modelling
Popular method to
Interpolate is “IDW”
Inversed Distance Weigh
Longitude
Latitude
Z Value
25. Popular method to Interpolate is “IDW”
Inversed Distance Weigh
Geostastistics Basics
26. Geostastistics Basics
• 2D Modelling
Used to model topography,
stratigraphic contacts,
isopachs, and water
levels
27. Geostastistics Basics
• 3D Modelling
There is simply the three-
dimensional version of
gridding.
The creation of Supercomputers
Used to model geochemistry, contaminants, ore
grades, metals, and geotechnical properties
28. Visualization
• Diagrams of grids and solids are more than "eye candy“
• Viewed in cross-section, fence diagrams, or block diagrams
• Comparing the original data with interpolated model
31. Volumetric Computation
• Model has been created
• Computing the volume : simple mathematical operation with cell values
• Usually in a “isopach map” layer selected
=
“isopach map” selected
• All cells added together (Total = 272 m), and multiplied by cell size ( 50 m x 50
m) ; referred as “Length x width” . The volume is 680.000 m3
• Then multiplied by density (Rho) of material was conversion factor (e.g. density
of coal = 1.826 metric tons per cubic meter). The tonnage is 1,2m metric tons)
32. Volumetric Computation
=
“isopach map” selected
• Volume = 272 m x 50 m x 50 m
= 680.000 m3
• Tonnage = 680.000 m3 x 1,826 metric tons / m3
= 1.241.680 metrics tons (1,2m metric tons)