Split-Online: Analysis

Using the processes image, the desired analysis is performed. Specific sizing algorithms are used to calculate run of mine rock fragmentation size vs. aggregate fragmentation size vs. pellet size.

Split-Online® Technical Tour
1.	Image Initiation and Acquisition
2.	Processing
3.	Analysis
4.	Results & Output

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Using the "binary" image produced in the fragmentation processing module, the size algorithms are then applied.

Fragmentation Measurement: The determination of the screen size and volume of each fragment from these characteristics are adequately described in Kemeny (1994) and Girdner et al. (1996).

The key challenge with measuring run of mine rock fragmentation is the range in particle size creates an under estimation of the smaller, finer material. There are two reasons that fines are not properly taken into account in images of rock fragments. First of all, the fine material is not always present on the surface of the fragments due to vibration, settling, wind, rain, compaction of the rocks, and other factors. Secondly, even if the fines are visible on the surface, the individual fragments are too small to be delineated properly.

The approach taken in the Split-Online Rock Fragmentation program to account for and estimate the fines consists of two parts.

In the first part, the upper size of fragments to be considered as fines (referred to as the finesize) is determined and the total percent of the material volume less than this size is determined. The finesize will be different for each image depending on the scale of the image.

The calculation of fines in an image comes from two sources: 1) the patches of fines on the surface of particles that are smaller than a few pixels so that they cannot be accurately outlined; and 2) particles smaller that the finesize along with the boundary pixels themselves. The size distribution module allows a different factor to be applied to each of these sources. The total area of fines in an image is the sum of each area times the appropriate factor. The volume ratio of fines to coarse particles is proportional to the area ratio.

The second step is to determine a realistic distribution for the fine material. Two options for the distribution within the fines are available in Split-Online, a Schumann distribution and a Rosin-Rammler distribution. Each of these distributions have two unknown parameters and these parameters are determined from two known points in the size distribution, one point at the finesize and the other at 1.5 times the finesize.

The calculation of the size distribution is done in a histogram using a large number of very small bins. The interpolation module allows the user to create the desired output sieve series and percentage axis size intercepts (F50, F80, topsize for example).

The Split-Online Aggregate Measurement program does not employ the fines estimation to reflect the fact that many aggregate products have been screened of fine material.

Pellet Measurement: The delineated pellet image is then fed to the Pellet Size Distribution module that calculates the pellet sizes. This module requires calibration to accurately report the size statistics. Using the size information, key metrics such as the Uniformity Index and the Size Guide Number can be calculated.