Geological Data for Blasting
A look at often available rock property data that will help map the course toward better blast designs...

Practical Blast Evaluation at the Minntac MIne
Routinely collected mine production data (e.g. Shovel speed, crusher speed, crusher amps) are used to evaluate the efficacy of changes in blast design...

Selection of Powder Factor in Large-Diameter Blast Holes
Paper documents the relationship between material handling and processing costs compared to blasting cost. Overall costs fell 5% when powder factor rose by 15%...

Stemming Selection for Large-Diameter Blast Holes
High-speed photography plus shovel & crusher productivity are used to evaluate various stemming practices...

Cap Testing at the Minntac Mine
This report summarizes field testing of non-electric delay caps. Nominal cap times may not reflect actual field results...

The Efficiency of Blasting Versus Crushing and Grinding
This paper discusses the relative efficiencies of blasting, crushing and grinding. Blast optimization should be expanded beyond mining and include processing costs. ...

Downstream Costs and Their Relationship to Blasting
Blasting may enjoy as much as a 3 to 1 cost advantage over grinding. This is important in metal mine/milling operations where ore is ground as fine as 60 microns ...

Blasting Down the Cost of Taconite Pellets
Minnesota iron ore producers are presented with several non-traditional innovations that could cut costs by nearly $100 million per annum...

Evaluation of Optical Sizing Methods
On-stream and grab sample size analysis methods are compared against...

Minnesota Iron Ore Blasting Practices
Minnesota iron oreblasting practices are described...

Are you Weatherwise...or are You Otherwise?
Blasters needn't be weathermen, but they should mind the skies ...

An Explosion in Mining
A LONG look back and a short look ahead at iron ore blasting ...

Optimized Iron Ore Blast Designs for SAG/AG Mills
Few mine to mill issues inspires as heated debates as blasting for SAG & AG mills. Increased blast energy may produce more surface area at a lower cost than mechanical milling. Decreased blast energy may, on the other hand, create more large pieces needed for grinding media. Rational allocation of energy in the comminution of ores is the essence of profitability and survival of taconite producers...

Improve Milling Through Better Powder Distribution
A Kuz-Ram model of Minnesota taconite, comparing the relative roles of higher powder factor to improved powder distribution ...

The Effects of Blasting on Crushing and Grinding Efficiency and Energy Consumption

Blasting has an important impact on mining and milling well beyond the necessary ability to dig and load the ore efficiently. There is an increasing body of blasting research indicating significant impacts in crushing and grinding. These include increased production through higher output and fewer delays for bridging and jamming by oversize...

Characterization of the Pre and Post Blast Environments

The closest measures that form ‘bookends’ to the blasting process are drill monitoring and optical size analyzers. Previously published work by: Thompson, Yin, Vynne and others; have relied on assorted known parameters against which drill monitoring data was compared....[Allow 30 seconds@49.9bps for pdf to load]

The Role of Blasting Operations in Metal Mining

Drill to mill process optimization remains an elusive goal. This paper explores some of the structural obstacles encountered in many large organizations ...

Blasting for Improved Autogenous Milling at Hibbing Taconite Company

Fully autogenous mills rely on the large, competent fraction of feed to act as grinding media. Research indicated that Hibtac mills require specific amounts of 6 to 10-inch ore. High recirculating loads require a steady influx of large rock. Blast designs, therefore, are presently characterized by wide patterns and low powder factors. Current efforts are aimed at improving mill throughput while reducing overall energy costs ...

Exploring the Data - Adding Value with Non-traditional Geologic Initiatives on Minnesota's Mesabi Range (slide show)

Underutilized data offer mine geologists a value creation opportunity that should be explored much the same as prospective ground. Large amounts of data are collected but not evaluated by geologists... Geologists, therefore, risk becoming task oriented. ... geologists can correlate in situ physical rock properties and drill-and-blast data with downstream mill performance. Drill monitoring data can map zones of varying grindability and bedding thickness. Geotechnical data from drill core can be block modeled to index fragment size.

Digital Delay Blasting At United Taconite LLC

In 2004, the mine began to experiment with programmable electronic detonators for improved blasting control due to the close proximity of surrounding communities..... Improvements were sought over the pyrotechnic based delays ability to provide the needed accuracy and fragmentation.

Size Matters on the Mesabi Range

This paper discusses the history of fragmentation analysis on the Mesabi Range in Minnesota. The history of image analysis is discussed and current static and on-line analysis technology is described.

Measurement and Analysis of Blast Induced Ground Vibration and Air Overpressure in the Vicinity of United Taconite LLC (339 MB PDF)

130 digital seismographs were deployed on May 2nd, 2007 to monitor the vibrations from one signature hole and 2 production blasts. Study was funded by the Iron Ore Cooperative Research Committee which is administered by the Minnesota Department of Natural Resources.