An explosion exerts a pressure impact on the charge chamber walls at levels of 1600 to 15 000 MPa, depending on the type of explosives used. This explosive impulse generates a pressure wave, spreading in all directions. Elastic waves bounce off the free surfaces and the surfaces of natural gaps undergoing reflections and refraction. Stretching stresses make gaps and fractures in the rock, eventually breaking it within the space of the explosive’s effectiveness.
The explosive centre, damaged by gas pressure, is ejected from the rock mass. It forms an action cone, consisting of an ejection cone and a crushing cone with different radius and height values, thus with a different action index.
Firing design
The following factors have to be considered in firing design:
– associated with rock mass, conductibility of sound waves, fracture density, compaction, etc.,
– associated with firing effects: output volume, break-up degree, the geometry of output slide after explosion (the height, the base width),
– associated with a risk of environmental impacts, such as seismic quakes, scatter of rock fragments, sound effects.
Giants in the industry
When ten years ago Liebherr beat the Guinness record with its rigid-frame T 282 B hauler, nobody could have guessed that any manufacturer would be able to construct a dump truck with a carrying capacity above 230 tons. However, this record has just been broken – the BielAZ Company has presented the 75710 hauler.
The 75710 model has the following parameters: length = 20.6 m, width = 9.87 m and height = 8.16 m, and its wheels are 4 m in diameter. The single load capacity of the tipper amounts to 500 tons, being thus an unrivalled solution. In order to put a BielAZ hauler in motion, there are two 16-cylinder, turbocharged diesel engines, each with 65 litre capacity,
Their total power amounts to 4600 HP, while the maximum speed is an impressive 64 km/h. There is no need, however, to worry about meeting this giant vehicle on the road, as this tipper is used exclusively in mining.
Aggregates are very common in many applications, including the building of houses, use as a base layer for asphalt-paved roads, and in concrete and asphalt manufacturing technologies. Aggregates are an excellent decoration for yards and gardens. Fine gravel is a perfect substratum for many rock flowers and provides very effective protection against the growth of weeds among plants. What is the average knowledge of aggregate types? We are afraid it is rather scarce. Nobody thinks about how they have originated and where they come from.
We most often divide aggregates into natural and artificially produced; other division criteria include their size and origin.
.
Construction aggregates:
These are used in the building industry – construction aggregates are characterised by very high compression strength and resistance against abrasion and other mechanical impacts.
Depending on their use, aggregates have to meet a number of standards and requirements, which gives the guarantee for the long life of building structures, constructed on aggregates bases, and ensures their safe use.
Road-construction aggregates:
Aggregates which are used for road construction, road-construction aggregates, have to comply with a number of standards and be characterised by a specific strength and friction coefficient.
Granites, basalts and porphyries, i.e. aggregates of the highest resistance to all outdoor factors and atmospheric conditions, are most often used in the road building industry.
Aggregate application::
In concrete production, similarly as in asphalt production, the main selection criterion is mechanical strength. Therefore, granite and basalt are used for the production of concrete with very high overload strength, while limestone and dolomite are used for the production of such concretes which demonstrate high mechanical strength with regards to load. However, their resistance may be slightly lower. Concrete covers, made of baryte, limonite, goethite and haematite, are another type of concrete, made of high strength aggregates.
The selection of the proper aggregate is of key importance in the building industry, since rocks are characterised by various degrees of mechanical strength and elasticity, which is of the utmost importance for the later use and functionality of the objects raised with aggregate application. In horticulture, both professional and in small home gardens, the aggregate selection criteria are most often based on the taste and the pocket of aggregate owners, since aggregate layers in such applications need not conform to any functional demands, except aesthetic requirements. Thus, nobody thinks about their hardness, elasticity or strength. Thus, the colour and thickness of grains are mainly taken into account.
The thicker the grains, the higher the price. A splendid example of aggregate use in yards are aggregate surface layers on driveways and garden paths, improving their drainage and irrigation features. Rainwater does not accumulate on the aggregate’s surface, thus eliminating mud formation; even after heavy rains, water permeates through the aggregate and soaks into the soil.
“The Regional Operational Programme of the Silesian province
is the real answer to real needs”
“The Regional Operational Programme of the Silesian province is the real answer to real needs”
Purchase of a mobile production line to manufacture dolomite fertiliser in order to introduce
a new product – mineral fertilisers – on the market by the TRIBAG S.A. Company.
The Beneficiary: TRIBAG SA
Project value: 516 600,00 zł
Funding value: 205 800,00 zł
The Project was co-funded by the European Union from the European Fund of Regional Development within the framework of the Regional Operative Programme of the Silesian province for the years 2007 – 2013.
See the www.rpo.slaskie.pl website for the background information on the Regional Operative Programme of the Silesian province for the years 2007 – 2013.