WP4 NEW EXPLOSIVE APPLICATION TECHNOLOGIES FOR SMALL MINERAL DEPOSITS

Maxam (lead), UPM

The overall objective of WP4 is to match explosives energy, density and rheology properties to a hardness rock model based on MWD inputs and study
the behaviour of ammonium nitrate leaching in different explosives formulations for a sustainable way of blasting.

4.1. EXPLOSIVE DEVELOPMENT

This task aims to develop explosives application technologies with different properties to match to different rock hardness models. The development is expected follow the following sequence:
Subtask 4.1.1 After the rock characteristics of a specific rock type have been defined jointly with other project partners, MAXAM will first help develop the range of blast designs to be used to blast that specific type of rock.
Subtask 4.1.2 MAXAM will develop an explosive specification sheet which will highlight the requirements that the explosive will need to fulfil and the conditions of the blast under which the explosive would be used. This master specification will define the range of explosive properties, specifically density, energy, velocity of detonation (VoD), fume class, and other parameters needed to use the explosive in the blast designs defined earlier.
Subtask 4.1.3 Explosive application development will be done in MAXAM’s facilities with expertise in developing and testing techniques and practices which exhibit the properties required. It is expected that MAXAM will develop up to five specifics techniques. The techniques will be flexible enough to permit customizing the explosive properties to reach the value desired for blasting either in the manufacturing plant or at the point of use.
Subtask 4.1.4 Deliver systems may also be developed (for example for bulk explosives) in case such systems are found to be the safest and most appropriate mechanism to deliver the explosive to the point of use.
Subtask 4.1.5 Laboratory tests will be carried out to study different explosives formulations properties as energy, VoD, power and strength. Below is a description of the proposed laboratory tests to be executed:
Density will be measured with a weigh scale and a container of a known volume
VOD will be measured with an electronic timer and a sensor cable
Power and strength will be measured with one or more of the following methods: ballistic mortar, Hess test, or other similar tests as required by a testing authority.
Viscosity will be measured with viscometers.
Energy will be calculated using standard software code.
Each explosive formulation and its delivery system will be tested for their propensity to leach into water under field conditions. Explosives will be loaded into boreholes with water, and the water will be monitored for its salt content at different times. The speed at which salts leach into the water will be then calculated to determine if the rate if the rate of leaching exceeds pre-established limits.

4.2. EXPLOSIVE CHARACTERISATION MODULE

This task’s main goal is to develop new modules for Rioblast® (MAXAM’s blast design Software) including the studies/numerical models that will be developed by project partners as fragmentation prediction, explosives characterization and rock mass hardness model. MAXAM will integrate the explosives characterization developed by UPM into blast design software as well as the rock mass hardness model.
Rock mass hardness will be displayed on a 3D model of the bench/pit or development heading showing the different rock characteristics so the blast design could be adapted to rock conditions. The software user will be able to design the blast in order to match the explosives characteristics to the different rock hardness areas, then, all this information will be used for the fragmentation prediction module which will show the rock sizes distribution expected for the real rock conditions, blast design and explosives characteristics.

4.3. EXPLOSIVES PROPERTIES CHARACTERISATION AND ITS USE IN BLAST DESIGN

In this task, several laboratory tests will be carried out to study different explosives formulations properties as energy, VoD, power and strength. Below is a description of the proposed laboratory tests to be executed:
Density will be measured with a weigh scale and a container of a known volume
VOD will be measured with an electronic timer and a sensor cable
Power and strength will be measured with one or more of the following methods: ballistic mortar, Hess test, or other
similar tests as required by a testing authority.
Viscosity will be measured with viscometers.
Energy will be calculated using standard software code.
Each explosive formulation and its delivery system will be tested for their propensity to leach into water under field conditions. Explosives will be loaded into boreholes with water, and the water will be monitored for its salt content at different times. The speed at which salts leach into the water will be then calculated to determine if the rate if the rate of leaching exceeds pre-established limits.

4.4. EXPLOSIVES TECHNIQUES TO REDUCE AMMONIUM NITRATE LEACHING

Following leaching tests, standards will be defined to specify which explosive and delivery system to use under a given blasting scenario to minimize leaching effects. If limits are exceeded, then the techniques will be changed and the configuration will be retested again. It is expected that explosives wrapped in waterproof packing or with high viscosities at the point of use be more resistant to leaching.

4.5. FIELD VALIDATION

All techniques will be validated in field testing in collaboration with project partners since an important part of explosive development is done with data collected during field tests. Field validation will include not only explosive delivery, but also, blast performance like fragmentation, muck pile shape, fumes, instantaneous dig rate and other blast KPI.

WP OVERVIEW