Anisotropic - Data that has a preferred direction, orientation, or trend is said to be anisotropic. A topographic ridge or an ore zone with constant strike and dip are examples of anisotropic data.
Assay - An assay is a quality or value that has been sampled or calculated from drill hole intervals. Assay values are processed in MicroMODEL as labels. (e.g. Label #1 represents Gold oz/ton assays) Assays are input into MicroMODEL with the drill hole intervals as labels, and later modeled as grade models or grids.
Azimuth - Angle measured clockwise from North to the primary axis of the anisotropic search ellipsoid.
Bearing - The bearing is the azimuth measured in degrees from North to the plan-view projection of a drill hole, ellipsoid axis, or variogram axis. This is also known as the dip direction of the line segment.
Bench (Level) - A planar horizontal surface at which a particular slice will be removed from the deposit. Benches are numbered sequentially starting at the bottom of the block model. MicroMODEL refers to a bench by either its bench (level) number or toe elevation.
Bench Composite - A bench composite is a drill hole interval which usually combines several sample drill hole intervals into an interval which starts at the top elevation of a bench and ends at the bottom elevation of the same bench. Therefore, each bench intercept in a given drill hole is represented by 1 (one) composite.
Bench Elevation - The elevation of the toe of a particular bench. This elevation is relative to the datum of the global survey system, not the bottom of the block model.
Bench Height - The height of the working face at which the deposit will be mined. This is also referred to as the bench thickness. The bench height determines the height of the blocks within the block model.
Bench Number - Level Number. The bench number is an integer corresponding to the sequential numbering of a bench with the bottom most bench being Number 1 and the top most bench is the number of benches in the block model.
Block - The smallest unit within the three-dimensional rock and grade model(s). The size of the block is defined by the row, column, and level dimensions specified in the Project Information File. When a rock or grade assignment is made to the centroid of a block, all material contained within the block is comprised of the assigned value.
Block Model - A three-dimensional matrix or grid comprised of individual blocks containing rock codes or grade values. The size of a block model is determined by the number of rows, columns, and benches entered in the Project Information File.
Cell - A cell is the smallest individual rectangular unit within a two-dimensional plan-view grid as defined by the intersection of a row and column. During topography modeling, elevations are estimated at each cell center by the grid modeling program. Block maps that are displayed in plan view are often referred to as cell maps.
Character Size - The character size on any scaled plot is determined by a fraction of the row dimension. (e.g. a character size of 0.15 produces character heights that are 15% of a cell's height or row dimension.) See Volume I, Section 6.3.8.
Character Height - The measured distance from the top to the bottom of a plotted character.
Clipping - Clipping isolates a rectangle within the model grid for modeling or plotting. The rectangle or clipped area is specified by its row and column ranges in the local grid.
Column - A column is a vertical "stack" of cells. The column number specifies the location, from left to right, of a cell within the local grid.
Composite - A composite is a drill hole interval which usually combines several sample drill hole intervals into intervals of constant length as determined by the compositing method (see Drill Hole, Bench and Rock Unit Compositing). Generally, compositing will reduce the number of data which the statistical, geostatistical, and modeling programs must process.
Compositing - A method of reducing the number of drill hole intervals within a database to intervals of equal length for a given drill hole.
Cone Surface - Any 2-D topography surface, numbered from 0 (reserved for starting topography grid) to 99. The surface doesn't necessarily represent a floating cone run, and can actually be a converted mined out pit surface from OPD. It can also be an updated surface which is output from the waste dump volume calculation program.
Cross Validation - Cross validation is a different term for the same process, point validation, where known sample or composite drill hole data values are removed in turn and then estimated from surrounding data. The statistical distribution of the real errors is then studied.
Digitize - The process of quickly entering Northing and Easting and elevation coordinates of polygon or contour data into MicroMODEL via an electronic device called a digitizer.
Drill Hole Composite - A drill hole interval which usually combines several sample intervals into an interval with a length equal to the bench height. The drill hole composites are developed down the hole from the collar.
Experimental Variogram - The variogram whose values are calculated from the actual data.
Floating Cone Algorithm - An automatic method for designing an open pit mine from a 3-D block model of grades.
Geologic Code - See Rock Code.
Global Grid - The global grid consists of the surveyed Northing, Easting, and elevation coordinate lines. Locations of data are generally specified relative to this grid with Northing, Easting, and elevation coordinates.
Grid - The MicroMODEL surface, rock and grade model(s) are stored as two-dimensional and three-dimensional matrices called grids. All grids in a database will have the same dimensions as defined by the number of rows, columns, and levels in the Project Information File. Each grid cell (topography) or block (rock and grades) contains values relative to the grid and label number.
IDP (Inverse Distance to a Power) - IDP is a method of point estimation which weights surrounding data points according to their Inverse Distance (from the point to the data point) to a user-specified Power. A power of 1.0 represents a linear interpolation, whereas a higher power approaches a polygonal estimation.
Isotropic - Data which does not have a preferred orientation or trend is said to be isotropic. If similar variograms can be obtained from several different directions, the data is probably isotropic.
Kriging - Kriging is a geostatistical method of point estimation which utilizes a variogram model for the given data set. Kriging calculates the weights to be given to each data point used in the estimation in order to provide the smallest possible error of estimation in average.
Label - A label is a type of quality or assay data such as Gold, %Fe, recovery, etc. Usually label values are associated with the drill hole intervals. These labels are then modeled to create grade models. New labels can be created with the manipulation programs.
Label Number - Each label has a label number which is used throughout MicroMODEL for identification. Refer to any MicroMODEL printed output header page for a list of the labels and their corresponding label numbers.
Level - See Bench
Local Grid - The local grid is the three-dimensional model matrix comprised of rows, columns, and levels. An individual block can be located by its row, column, and level numbers on the local grid.
Log Normal - Data that is log-normally distributed demonstrates a linear relationship when plotted on a logarithmic cumulative frequency plot.
Manipulation - Manipulation is the process of updating or creating drill hole interval and grid labels with a series of algebraic functions. (e.g. a GOLD grid could be manipulated to an ORE grid to locate the blocks that are above a 0.045 oz Au/ton cutoff)
Matrix - A matrix in MicroMODEL is a two-dimensional or three-dimensional grid of values which corresponds to the number of rows, columns, and levels of the model. A grid.
Model - Generally "the model" implies the entire database including drill holes, topography, rock, and grade grids. The term model is also used when referring to a grid, as in "the Gold Grade Model."
Modeling - Modeling is the process of estimating the value of a point based on surrounding data. Generally, modeling produces a two or three- dimensional grid or model which is subsequently analyzed. Modeling can also be used to compare known vs. estimated values as in point validation.
Money Matrix - A 3-D grade model that contains the net value that mining each particular block would generate. Calculation of the net value includes recovery, metal price, processing costs, and mining costs. A money matrix must be created prior to running the floating cone program.
Nugget - The nugget is the discontinuity jump often observed at the origin of the variogram. It represents residual variability at a very short range, including microstructures, erroneous data, assaying white noise, and random components of the grade itself. Note that the value of the variogram for distance zero is always exactly zero.
Nested Variogram - A combination of two or more variogram models.
Pit Model - A pit model is a copy of the rock model that has negative rock codes where mining has already occurred.
Plunge - Plunge is the vertical angle in degrees from horizontal to a drill hole, ellipsoid axis, or variogram axis. This is often referred to as the dip angle of the drill hole or line segment. Downward dipping line segments have positive plunge. Horizontal segments have 0.0 degree plunge whereas vertical segments have +90.0 degree plunge.
Point Validation - Point validation and cross validation are different terms for the process of comparing a known point's value with the value a modeling program would estimate at the same point. This is a useful tool used to compare modeling parameters and methods as the difference of the known and estimated values will decrease as the modeling procedure is improved.
PostScript - A printer graphics interface file format.
Presort - Prior to modeling with kriging or IDP, data must be sorted. The presort accomplishes this task by determining which data points can be used to estimate each unknown point according to user specified parameters.
Project Information - The project information is the data that is needed by every program within MicroMODEL. The data is stored in the Project Information File. This file contains the number and dimensions of the rows, columns, and levels, number and names of the labels, Project Title, etc.
Quality - A quality is an assay or value that has been sampled or calculated from drill hole intervals. Quality values are processed in MicroMODEL as labels. (e.g. Label #3 represents % recovery) Qualities are input into MicroMODEL with the drill hole intervals as labels, and later modeled as grade models.
Rake - The third rotation applied as an azimuth angle within the plane defined by the primary and secondary axes for defining the anisotropic search ellipsoid. See also Tilt.
Range - The range of a variogram is the distance at which the data shows no correlation.
Rock Code - A number between 0 and 9999 that represents a certain geologic and/or geotechnical condition. In MicroMODEL, 0 (zero) is defined as air.
Rock Model - A three dimensional grid whose block values are geologic (or rock) codes. These codes are used for defining areas of like geologic of geotechnical conditions.
Rock Unit Compositing - Composite values can be calculated as a weighted average, spanning a single geologic unit ( rock code).
Rotation Angle - The rotation angle is an azimuth clockwise from North to the specified line (left edge of the model or ellipse axis)
Row - A row is a horizontal series of cells extending from the left to the right edge of the local grid. The row location is specified by its row number.
Runtime Title - The runtime title appears on some MicroMODEL output. It is usually used as an identifier of specific parameters or characteristics.
Sample - A sample is one drill hole interval and the rock code and assay information associated with that interval. Generally this information is as it appears on the drill hole logs from the field. Therefore, a sampled drill hole database contains drill hole information prior to compositing.
Scale Factor - The scale factor determines the size of MicroMODEL plots. For scaled plots this is the map scale at which the plot is desired. For unscaled plots the scale factor is generally 1.0 for a standard report size plot.
Scaled Plot - A scaled plot is a true to scale map produced by the plotter. All scaled plots require a user-specified map scale in either feet/inch or meters/meter. Scaled plots are: drill hole locations, mid-bench pierce point locations, cross sections, cell maps, contour maps, block cross sections, and perspectives.
Semivariogram - See Variogram.
Sill - The sill is the possible variogram value around which the variogram stabilizes when distance increases. Not all variograms have a sill. If a sill exists, the distance where the sill value is reached is called the range. The range is the distance behind which variable values at two points no longer demonstrates any correlation.
Submodel - Submodeling allows the user to model a rectangular portion of any grid by specifying clipping during the modeling presort.
Surface - A two-dimensional grid containing elevations which defines the boundary between rock and air.
Tolerance Band - A minimum search tolerance measured perpendicular from the variogram search axis.
Topography - See Surface.
Transformed - Transformed data is data which has been reduced to its decimal logarithms.
Trend Surface - A trend surface is an Nth order polynomial surface fit through the prepared surface data. A first order trend surface results in a best fit plane through the data whereas higher orders produces more detailed surfaces.
Tilt - The rotation of the tertiary axis clockwise around the primary axis for defining the anisotropic search ellipsoid. See also Rake.
Universal Kriging - A kriging technique that is used in the presence of drift.
Unscaled Plot - Statistical and geostatistical plotted output are unscaled plots. Generally, a scale factor of 1.0 will produce a convenient report sized plot.
Variogram - A measure of the variance between data as a function of distance.
Variogram Model - A definition of a curve which fits the points on an experimental variogram. The variogram model is required during geostatistical modeling.
Window Angle - The angle, in degrees, defining a variogram search area.