testwork
| Testwork Programs That Deliver Multiple Data Sets
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.
(Presented at Procemin 2008, Santiago, Chile) [↑ read less ↑]
Mining projects are applying the age-old notion of "check your work" against comminution circuit design, mill ...[↓ read more ↓]
| Alex Doll | |

testwork
| Effect of Sample Dimensions on Comminution Testwork
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.
(Presented at Procemin 2009, Santiago, Chile) [↑ read less ↑]
Comminution tests on a particular project have displayed completely different breakage characteristics relativ...[↓ read more ↓]
| Alex Doll | |

testwork
| Comparison of UCS to Bond Work Indices
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. [↑ read less ↑]
Unconfined Compressive Strength (UCS) is a commonly used rockmass strength measurement used by rock mechanics ...[↓ read more ↓]
| Alex Doll | |

testwork
| Testwork template spreadsheet
Blank spreadsheet that is pre-populated with the field names needed to import laboratory test results into the SAGMILLING.COM circuit model testwork database (subscription required).
Enter your test results, one per row, arranged into the columns indicated.
To import into your testwork database, copy the block of cells starting with the top row down to the bottom of your data. Paste this block into the import field in the website "add testwork" page (do not worry if the text looks scrambled, the website can understand it). [↑ read less ↑]
Blank spreadsheet that is pre-populated with the field names needed to import laboratory test results into the...[↓ read more ↓]
| Alex Doll | |

testwork
| Calculating DWi from a drop weight test result
The drop weight test is a common laboratory measurement used to determine the comminution characteristics of rock samples. A common metric derived from a drop weight test is a value "A×b". Another common metric that is derived from the SMC Test™ variant of a drop weight test is a "Drop Weight Index", abbreviated as DWi. This work looks at a public database of test results to determine a relationship for DWi as a function of A×b. [↑ read less ↑]
The drop weight test is a common laboratory measurement used to determine the comminution characteristics of r...[↓ read more ↓]
| Alex Doll | |

testwork
| Commentary on the apparatus of the Bond rod mill work index
The Bond "Third Theory" of comminution was originally divided into three size classes reflecting the varieties of comminution equipment common during the time period when Bond (and his collaborators) were gathering the information to calibrate comminution models. The middle size class, represented by rod milling, is fitted to a tumbling test, referred to as the Bond rod mill work index (Wi RM , or RWi).
The apparatus used to determine this work index was described in 1943 by Bond & Maxton. Unfortunately, there are some laboratories that have deviated from the apparatus specified by Bond & Maxton and there are modern comminution models that are calibrated to this non-standard mill geometry. (document revised 2016-04-27) [↑ read less ↑]
The Bond "Third Theory" of comminution was originally divided into three size classes reflecting the varieties...[↓ read more ↓]
| Alex Doll | |

testwork
| Database of public grindability testwork
Spreadsheet that accompanies the Procemin 2016 paper by Alex Doll. This spreadsheet contains a database of public grindability testwork for projects worldwide. The data is collected mostly from conference papers and NI 43-101 reports. The NI 43-101 data may not be used for commercial purposes (hence it is being given away); but it may be used for research purposes such as model calibrations and project benchmarking. [↑ read less ↑]
Spreadsheet that accompanies the Procemin 2016 paper by Alex Doll. This spreadsheet contains a database of pu...[↓ read more ↓]
| Alex Doll | |

testwork
| A public database of tumbling mill grindability measurements and their relationships
This work presents a public database of over 800 grindability measurements and a set of equations for converting between different grindability tests based on this database. Several laboratory grindability measurements commonly used in the mining industry; each is generally applicable to a particular grindability model and is incompatible with other models. Conversion between different test types is possible using a series of empirical relationships between those tests conducted at similar size classes.
The commonly used grindability tests included in the database are the Bond work indices for ball milling, rod milling and crushing; the drop weight test results A, b, A×b, DWi, Mia, Mic, Mih and ta; SAG grindability index, SGI or SPI™; and other values such as Mib and point load index.
Some examples of power-based model specific energy predictions will be compared to published mill surveys to observe how well the different models predict the specific energy of an industrial mill. [↑ read less ↑]
This work presents a public database of over 800 grindability measurements and a set of equations for converti...[↓ read more ↓]
| Alex Doll | |

testwork
| Effect of core diameter on the Bond impact crushing work index test
The Bond low energy impact (crushing) work index test is specified to be performed on rock specimens between 50 mm and 75 mm in effective diameter. NQ-diameter drill core, frequently used in mineral exploration programs does not meet that specification, it being 45 mm diameter or less.
This paper reports the effect of performing the impact test on contiguous sections of HQ diameter and NQ diameter core, exploring the hypothesis that the contiguous intervals give equivalent results in spite of the core diameter difference. [↑ read less ↑]
The Bond low energy impact (crushing) work index test is specified to be performed on rock specimens between 5...[↓ read more ↓]
| Alex Doll | |