modelling
| Rosin Rammler Regression Spreadsheet
Spreadsheet calculation that fits the Rosin Rammler equation to a set of particle size data consisting of an arbitrary quantity of results.
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Spreadsheet calculation that fits the Rosin Rammler equation to a set of particle size data consisting of an a...[↓ read more ↓] [download]
| Alex Doll | |
modelling
| Fitting a Rosin Rammler equation to a 2-value data set
Calculation provides a quick way to estimate the Rosin Rammler equation parameters by using two data values to fit the two parameters, Dn and n
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Calculation provides a quick way to estimate the Rosin Rammler equation parameters by using two data values to...[↓ read more ↓] [download]
| Alex Doll | |
modelling
| JK Ball Mill Model Notes
Review of the JKMRC Mineral Comminution Circuits textbook (Reference 1), and discussions with practitioners of the JKSimMet software have led to the following simplified description of the opera- tion of the JK method for modelling a ball mill. A scenario of scaling up a pilot plant test to a full sized circuit is assumed in this discussion.
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Review of the JKMRC Mineral Comminution Circuits textbook (Reference 1), and discussions with practitioners of...[↓ read more ↓] [download]
| Alex Doll | |
modelling
| UBC MINE331 Lecture Notes
Memorandum describing the SAG mill & ball mill circuit sizing lecture delivered to the University of British Columbia mill design course (MINE331). Uses the "Bond Work Index" method developed by Barratt to size circuit power requirements from bench-scale testwork. (Revision 6, Nov 2015)
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Memorandum describing the SAG mill & ball mill circuit sizing lecture delivered to the University of British C...[↓ read more ↓] [download]
| Alex Doll | |
modelling
| Liner Effective Height
Determines the effective mill inside diameter of a given set of "top hat" lifters for use in mill volume and critical speed calculations.
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Determines the effective mill inside diameter of a given set of "top hat" lifters for use in mill volume and c...[↓ read more ↓] [download]
| Alex Doll | |
modelling
| Liner Effective Height
Determines the effective mill inside diameter of a given set of "top hat" lifters for use in mill volume and critical speed calculations.
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Determines the effective mill inside diameter of a given set of "top hat" lifters for use in mill volume and c...[↓ read more ↓] [download]
| Alex Doll | |
modelling
| MillFillingCalc
Backup to the Mill Filling Calculation spreadsheets that describes the geometry and mathematics.
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Backup to the Mill Filling Calculation spreadsheets that describes the geometry and mathematics....[download]
| Alex Doll | |
modelling
| A comparison of SAG mill power models
SAG Mill power draw models are used in mill design and grinding circuit modelling to predict how much power will be consumed by a particular mill geometry and operating configuration. This paper will compare SAG mill models by Morrell, Loveday (using "Power Numbers" published by Barratt) and Austin against several published mill surveys. The purpose of the comparison is to identify the "fitting factors" used by each model and to identify which mill configurations seem to better suit each model.
The importance of conducting surveys suited to model calibration will be highlighted because the review of literature shows that survey information important to modelling is often either missing or omitted.
A recommendation for the collection of data during a mill survey is presented, along with some assumptions used by the Author in the absence of certain data. The benefit to mining companies of publishing their survey data, and thereby allowing modellers to improve their model calibration, is discussed.
The comparison of models requires a discussion of the measurement of power in a mill drive system as the models use slightly different basis for "where power is measured". The benchmarking of models against plant operations requires a similar discussion of power measurement.
(Presented at Procemin 2013, Santiago, Chile)
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SAG Mill power draw models are used in mill design and grinding circuit modelling to predict how much power wi...[↓ read more ↓] [download]
| Alex Doll | |
modelling
| A simple estimation method of materials handling specific energy consumption in HPGR circuits
Multi-stage crushing plants, including high pressure grinding roll (HPGR) circuits, require more materials handling equipment than SAG and ball mill circuits. A temptation exists to neglect the energy consumption of materials handling when doing desktop comparisons of HPGR versus SAG milling circuits because estimation of materials handling power requirements can demand significant general arrangement drafting that is not available when performing preliminary scoping or "desktop" studies.
The largest component of materials handling power is consumed by conveyors when lifting material between stages of crushing, meaning that a simple potential energy model can be used to evaluate conveying specific power consumption. This potential energy consumption for conveying can then be factored to provide overall materials handling specific energy consumption suitable for desktop studies of HPGR and other multi-stage crushing circuits. The technique also permits different crushing circuit flowsheets to be evaluated, at a preliminary level, by simply counting the number of times a conveyor must "lift" ore from ground level up to a bin or other equipment mounted up high.
(Presented at CMP 2015, Ottawa, Canada; represented as a poster at Procemin 2015, Santiago, Chile)
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Multi-stage crushing plants, including high pressure grinding roll (HPGR) circuits, require more materials han...[↓ read more ↓] [download]
| Alex Doll | |
modelling
| SAG power draw survey tabulation
This LibreOffice spreadsheet contains the raw data used to create Table 1 and Table 2 of the paper "An updated data set for SAG mill power model calibration", presented at IMPC 2016 in Quebec City, Canada in September, 2016. Refer to the paper for the definitions and meanings of the different columns.
The file format should be completely compatible with OpenOffice software, and mostly compatible with Microsoft Excel (the charts will probably not work in Excel).
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This LibreOffice spreadsheet contains the raw data used to create Table 1 and Table 2 of the paper "An updated...[↓ read more ↓] [download]
| Alex Doll | |
Modelling
| An updated data set for sag mill power model calibration
This paper expands the SAG mill survey database published by the Author at Procemin 2013. The new database includes 49 published SAG/AG mill surveys and includes mills from all over the world. The paper will compare the survey database to SAG mill models by Austin, Morrell and Hogg & Fuerstenau with the purpose of demonstrating the degree of fit of the models to surveys and validating any empirical “fitting factors” used in the models.
SAG mill power draw models are used in mill design and grinding circuit modelling to predict how much power will be consumed by a particular mill geometry and operating configuration. The importance of conducting surveys suited to model calibration will be highlighted because the review of literature shows that survey information important to modelling is often missing or omitted. A recommendation for the collection of data during a mill survey is presented, along with some assumptions used by the Author in the absence of certain data. The benefit to mining companies of publishing their survey data, and thereby allowing modellers to improve their model calibration, is discussed.
The comparison of models requires a discussion of the measurement of power in a mill drive system as the models use slightly different position in the electrical network for "where power is measured". The benchmarking of models against plant operations requires a similar discussion of power measurement. (paper published at IMPC 2016)
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This paper expands the SAG mill survey database published by the Author at Procemin 2013. The new database in...[↓ read more ↓] [download]
| Alex Doll | |
modelling
| Fine Grinding, A Refresher
Paper presented at CMP 2017.
Many power-based grinding models exist, and most operators are familiar with Fred Bond's "third theory". Bond's model is most commonly used to describe primary and secondary grinding to product sizes above, for example, 100 μm. Operators sometimes use Bond's equation to describe grinding in situations where it is not appropriate, such as fine grinding below 50 μm. Using an alternative model would be a better choice in this situation.
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Paper presented at CMP 2017.
Many power-based grinding models exist, and most operators are familiar with ...[↓ read more ↓] [download]
| Alex Doll | |
modelling
| Fine Grinding speaker notes
Speaker slides for CMP 2017 presentation "Fine Grinding, A Refresher"
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Speaker slides for CMP 2017 presentation "Fine Grinding, A Refresher"...[download]
| Alex Doll | |
modelling
| Power-based modelling of single-stage SAG
Paper presented at Procemin 2017.
Comminution circuit design and geometallurgy is normally performed using the power-based class of models. Many models of this type exist and all of them are empirically based, meaning they are calibrated to fit a specific set of laboratory results to a database of mill surveys. Most empirical comminution models are calibrated to two-stage AG/SAG mill and ball mill circuits -- this work compares the performance of several commonly used power-based models to surveys conducted on single-stage AG/SAG circuits.
Survey data was collected from Anglo American’s El Soldado mine and from published works by others and the operating specific energy consumption of circuit was computed. Ore grindability measurements were collected, allowing model predictions of specific energy consumption to be computed using models proposed by Jorquera & Becerra (at El Soldado), Morrell, Barratt and Amelunxen. The actual operating specific energy consumption is finally compared to the
predictions.
The more complex ores required more complex models to obtain reliable predictions; whereas, the simple ores can be modelled by any of the models. A complex ore, such as Palabora, requires grindabililty measurements be made at three size classes, such as the three Bond work indices. A simple ore, such as El Soldado, can be reliably modelled with a single grindabily measurement, such as the SAG Grindability Index. A quick diagnostic of whether an ore is “complex” or “simple” is to compare the three Bond work indices: “simple” ores generally have the same value for all
three work index values, whereas “complex” have dramatically different values for all three.
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Paper presented at Procemin 2017.
Comminution circuit design and geometallurgy is normally performed using ...[↓ read more ↓] [download]
| Alex Doll & Miguel Becerra | |
modelling
| A simple method of assessing ball mill health using bond tests and functional performance
Health checkups are just as important for grinding circuits as for grinding circuit operators. This paper describes a process for performing a non-intrusive survey of the operating plant (no mill shut-downs required), collecting a sample of plant feed for testing at a commercial laboratory, and then interpreting the survey to decide if further investigation is needed. If the health check comes back "clean", then the mill is declared healthy and no further work is needed. If the health check comes back "sick", then the Functional Performance equations identify which part of the grinding circuit is operating poorly and future corrective action can be tailored to that unit operation. A case study of a grinding circuit survey conducted at the Detour Gold Corporation mine in Ontario demonstrates the process.
Functional Performance has been used for many years to disentangle different types of ball mill circuit efficiencies. The novel component of this work is to use a set of standard Bond ball mill grindability tests at different closing mesh sizes to generate a "Levin B" metric which is then substituted into the Functional Performance ball mill grinding efficiency equation to determine the industrial mill's efficiency as a percentage of the laboratory mill's efficiency. This removes the ore hardness as an unknown variable, providing a simple percentage score rather than the arcane metric returned in the conventional Functional Performance grinding efficiency metric.
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Health checkups are just as important for grinding circuits as for grinding circuit operators. This paper desc...[↓ read more ↓] [download]
| A. Doll, A. Morneau, J-F. Dupont, and D. Michaud | |
modelling
| PSD model summary
Tabulate a summary of which Particle Size Distribution (PSD) models is the best fit for industrial data collected by AGD’s customers. The regression equations used include the Gaudin-Schuhmann model, Rosin-Rammler model, and the Bond root-2 model.
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Tabulate a summary of which Particle Size Distribution (PSD) models is the best fit for industrial data collec...[↓ read more ↓] [download]
| Alex Doll & Munashe Kurisa | |
modelling
| Rosin Rammler Regression Spreadsheet
Spreadsheet calculation that fits the Rosin Rammler equation to a set of particle size data consisting of an arbitrary quantity of results.
[↑ read less ↑] [download]
Spreadsheet calculation that fits the Rosin Rammler equation to a set of particle size data consisting of an a...[↓ read more ↓] [download]
| Alex Doll | |
modelling
| Presentation at Universidad Privada del Norte, Cajamarca, Perú
Speaker slides from presentation made at the Universidad Privada del Norte, Cajamarca, Perú, November 25, 2015.
Topic is geometallurgy and the use of process model parameters integrated into a mine production block model to improve the forecasting of production, optimize pit designs, and permit the calculation of profit by block (instead of using a single cut-off grade).
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Speaker slides from presentation made at the Universidad Privada del Norte, Cajamarca, Perú, November 25, 201...[↓ read more ↓] [download]
| Alex Doll, Dave Michaud | |