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show all | mass balancing | modelling | testwork
 | Generic Sample Collection Protocol Diagram |
| Topic: testwork | |
| Work flow diagram depicting a generic sample collection protocol that collects samples for Bond Work Index testing, SPI samples and SMC/JK Drop Weight samples. Diagram-GenericSampleProtocol.pdf | |
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| Motor Power Measurement and Efficiency Diagram |
| Topic: modelling | |
| Grinding circuit power is commonly used as a defining parameter in circuit design and analysis. However, the circuit power can be defined at a number of points, and depending upon the use of the power, different system losses must be applied to the power reported. Further, different comminution models report power measured at different locations. TechMemorandum-MotorPower-Rev4.pdf | |
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| Fitting a Rosin Rammler equation to a 2-value data set |
| Topic: modelling | |
| 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 RosinRammlerFitting.pdf | |
 | Rosin Rammler Regression Spreadsheet |
| Topic: modelling | |
| Spreadsheet calculation that fits the Rosin Rammler equation to a set of particle size data consisting of an arbitrary quantity of results. RosinRammlerRegression.xls | |
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| Solving Mass Balances using Matrix Algebra |
| Topic: mass balancing | |
| Matrix Algebra, also known as linear algebra, is well suited to solving material balance problems encountered in plant design and optimisation. A properly constructed matrix is not sensitive the iterations of circular calculations that can cause 'hard wired' spreadsheet mass balances to fail to properly converge and balance. This paper demonstrates how to construct equations and use matrix algebra on a typical computer spreadsheet to solve an example mass balance during a mineral processing plant design. MassBalance-MatrixMethod.pdf | |
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| Performing Metallurgical Calculations on Spreadsheets |
| Topic: mass balancing | |
| Computerized spreadsheets are a commonly used tool in the engineering industry. Unfortunately, they are a very generic tool, and do require care when used to perform process engineering calculations. This paper describes many tools and tricks developed in the consulting engineering industry to make calculations more readable and to perform quality assurance. MassBalance-Spreadsheet.pdf | |
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| Testwork Programs That Deliver Multiple Data Sets |
| Topic: testwork | |
| Mining projects are applying the age-old notion of "check your work" against comminution circuit design, mill power requirement estimates and mill throughput estimates. The best way to test the results of one comminution modelling system is to replicate the calculation in a different modelling system. Unfortunately, the most common comminution modelling systems require largely incompatible test programs to provide input parameters. This paper presents some example protocols for sample collection and preparation from drillcore that simultaneously returns comminution datasets suitable for a Bond Work Index based method, an Axb dataset, and a set of SPI results. By carefully collecting data for all three methods, high quality geometallurgical dataset can be created Procemin08-ComminutionTestworkProgram.pdf | |
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| Effect of Sample Dimensions on Comminution Testwork |
| Topic: testwork | |
| In several recent consulting assignments, DJB Consultants Inc. has found that comminution tests on a particular project have displayed completely different breakage characteristics relative to a database, depending upon which test procedure was performed. Some of these differences are attributed to the dimensions of the sample that is presented to a test, e.g., a Bond crushing test compared to a ball mill test, while other differences can be attributed to a hardness profile that is inherent in a particular size class compared to another coarser or finer size class, e.g., fracture density and mineral filling and/or grain size. Ore types can respond with a characteristic hardness profile by size which may not be identified if only one sampling and testwork regime is used. Procemin09-EffectOfSampleDimensionsOnTestwork.pdf | |
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| JK Ball Mill Model Notes |
| Topic: modelling | |
| 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. TechMemorandum-JK_BallMill-Rev1.pdf | |
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| Crushing Work Index Comparisons Between Labs |
| Topic: testwork | |
| It has come to the attention of DJB Consultants, Inc. that practitioners of mineral comminution are questioning the Bond Low Energy Impact Crushing Work Index (WiC) results of a particular laboratory. It appears that this is based on a presumption that the DWI results of a SMC tests can be used as a proxy for WiC. DJB Consultants, Inc. believes this assumption is false in general, but can be locally true for particular ore types. Because the underlying assumption is generally false, the conclusion "there is a bias in results of labs" is also believed to be false. TechnicalMemorandum-CrushingWorkIndex.pdf | |
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| Comparison of UCS to Bond Work Indices |
| Topic: testwork | |
| Unconfined Compressive Strength (UCS) is a commonly used rockmass strength measurement used by rock mechanics practitioners. This paper examines potential relationships between UCS and Bond Work Index values (crushing, rod mill and ball mill). Data from 11 mines located around the world is analysed for correlations between UCS and various Wi values. UCS_Wi_paper.pdf | |
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| Sizing and Selection of Hydrocyclones |
| Topic: modelling | |
| Provides a basis for first-pass hydrocyclone sizing for mineral processing applications. Method is based on The Sizing and Section of Hydrocyclones by Richard Arterburn of Krebs. SizingAndSelectionOfHydrocyclones-Rev2.xls | |
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| Grinding: Why So Many Tests? |
| Topic: testwork | |
| There are a number of comminution tests commonly used in the mining industry. Many of the tests are used for a particular grinding model or mill sizing program and are incompatible with other tests of different models. This paper provides an overview of the commonly used grinding & crushing tests, which models (or practitioners) use a particular combination of tests, and draws some relationships between the incompatible tests based on the DJB Consultants Inc. database of projects. Case studies will demonstrate similarities and differences between major mining districts with some comments about homogeneous and heterogeneous behaviour within the grindability results. CMP2011-DollBarratt-GrindingTests.pdf | |
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| Choosing the Right Motors for your Mills |
| Topic: modelling | |
| Slide presentation providing an overview of the process for selection motors for grinding mills. Motors are selected based on "mill overload" conditions that are more rigorous than the mill process conditions. Procemin10_SelectingMotors.pdf | |
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| Microcracking versus the Phantom Cyclone |
| Topic: modelling | |
| Both Semi-Autogenous Grinding (SAG) mills and High Pressure Grinding Rolls (HPGRs) create more product fines than cone crushers or rod mills. Many recent HPGR papers claim benefits of these additional fines (often referred to as “microcracking”) when comparing to “standard” circuits involving cone crushers. An analogous effect is observed in SAG milling, where pilot plants and operations demonstrate more fines being produced than the same “standard” circuits. Some SAG milling designers employ a modelling technique called a “phantom cyclone” to “correct” the SAG mill product to make it match a “standard” ball mill feed (molienda unitaria) particle size distribution, which has the net effect of reducing the power demand of the secondary ball mills. Procemin10_Microcracking_PhantomCyclone.pdf | |
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| UBC MINE331 Lecture Notes |
| Topic: modelling | |
| 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. TechMemorandum-Mine331-Rev2.pdf | |