CHOICE of a LOADING - TRANSPORT SYSTEM ( Load and haul )

   After preliminary studies it is also necessary to combine the different loading and transport techniques in order to obtain the system which presents the best compromise " price - operating constraints" and in particular the environmental constraints. This choice is defined on the basis of the following parameters:  

• Nature and hardness of the materials to be extracted 
• Production to be ensured
• Transport distance 
• Need to crush the materials before their recovery for further processing 
• Opportunity to create stocks (marketable materials, ores , topsoil) or fill (waste)  

Although there are many combinations that can optimize the rolling load function we will describe as an example, the most common and especially those that use the most frequently encountered materials:
a) Hard materials slaughtered at l explosive


Distances less than 200 m. - Low or medium flow

The loading machine, also carries the transport. In this configuration a suitably calculated wheel loader provides these two functions.
This solution is widely used in quarry aggregates when it is equipped with a mobile crusher or it is to build stocks of aggregates all coming.
The wheel loader has the advantage of its mobility and its fast speed of travel which can reach 25 km/ h under load. It can virtually adapt to all driving conditions.

The economically profitable use of a loader used in loading - transport is below 150 to 200 m. depending on the driving conditions.
When the materials of the track are sharp tire wear is important and the profitability of such transport decreases rapidly. It is the same if the track is in bad condition because number of rotations / hour decreases. To improve track stability in poor condition most modern machines are equipped with an anti-pitching system. However, it is worth remembering that obtaining a good cost price is inseparable from the good maintenance of the slopes.  

Distances greater than 200 m. but less than 2000 m.

 This diagram represents the most common configuration for medium to large flows. On a rough terrain with slopes not exceeding 8 to 10%, rigid dump trucks will be chosen which are more economical to buy and less expensive to maintain than articulated haulers. These funds will be reserved for TP construction sites in muddy or hilly terrain or the exploitation of gravel pits in unstable terrain with low traction

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Pillar Design

The Safety Factor (SF) is the pillar strength divided by the pillar load.
Safety Factor = Pillar Strength / Pillar Load
                    
Pillar Strength – is a function of both a size effect and a shape effect.
1. Size Effect
2. Shape Effect
Size Effect – The average strength decreases as specimen size increases. ....

Mine planning and design (Yangon Technological University)

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Free Convert -Portable software- version 4.1

Convert is a free and easy to use unit conversion program that will convert the most popular units of distance, temperature, volume, time, speed, mass, power, density, pressure, energy, and many others, including the ability to create custom conversions!

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Comparison of Two Techniques Presplitting and Smooth Blasting

Drilling and blasting methods have been extensively applied to rock excavation in mining and civil engineering due to its low cost, high efficiency, and easy operation. However, some inevitable negative effects are often encountered under the blasting loads, such as blast-induced damage and vibration. To minimize and reduce these problems, presplit and smooth blasting as the advanced control techniques have been widely introduced into blasting design .  
Souce: Zilong Zhou and others. 

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Introduction à la cristallographie (Langage: french)

Avant-propos
 Chefs d'oeuvres de lo nature, par leurs formes géométriques, les cristaux reflètent l'arrangement périodique des atomes qui les constituent.
Cette phrase résume tout le champ d'étude de ¡a cristallographie. Celle-ci est donc l'étude des relations étroites qui relient les formes des cristaux et leurs propriétés physiques et la façon dont les atomes s'arrange dans l'intimité de leur architecture.
Cet ouvrage est destiné avant tout aux étudiants en géologie qui abordent l'étude de la minéralogie. 
Il s'adresse aussi aux amateurs de minéraux qui voudraient élargir leurs connaissances scientifiques au delà du simple plaisir de contempler un beau cristal.
La cristallographie est une discipline abstraite dont l'étude conduit vite à des formulations mathématiques compliquées. Dans cet ouvrage, je me suis efforcé de recourir le moins possible aux raisonnements purement mathématiques en choisissant une approche empirique des phénomènes.
Le contenu de ce livre résume tout ce qu'un étudiant en géologie devrait connaître avant d'aborder l'étude de l'optique cristalline et de la minéralogie descriptive.
L'amateur de minéraux peut très bien se limiter à l'étude des principaux chapitres qui l’intéressent, en laissant de côté ceux qui lui semblent trop rébarbatifs, tels ceux qui abordent le calcul cristallographique, la projection stéréographique, voire même la cristallochimie.
C’est dans un souci de clarté que la nomenclature utilisée ici a été choisie.
Après avoir assimilé la théorie contenue dans cet ouvrage, les lecteurs qui voudraient approfondir davantage la cristallographie pourront alors adopter sans difficulté les abréviations internationales en usage dans la littérature anglo-saxonne. Jacques Deferne.

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Open-pit, Block size selection and its impact on design and mine planning

This work evaluates and characterizes the impact of the support size and mining dilution of a block model in the operation and selection of equipment at an open pit mine. An exploratory analysis and
geostatistical modelling of the grades assayed on a set of drill hole samples is performed, which allows constructing a grade model on a dense grid by means of a conditional simulation. The grades are then averaged to greater selective mining unit supports in order to proceed with the study and methodology.
First, the metal-tonnage curves are used to analyse the loss of selectivity on the in situ resources caused by a change of support.
Concerning the ore reserves and their mining sequence, defined in the pit optimization and analysis process, the same curves prove that the loss of selectivity is more accentuated. Second, the importance of the block boundary dilution produced during mining operations is assessed. Its value depends on the amount of ore in contact with waste, on the loading error of the equipment and on
the ore loss/waste dilution criterion assumed by the planner. The dilution percentage and the differences between waste and ore grades become higher when the block size decreases. For these
reasons, considering the dilution in the production plans makes mining a small support more constraining. An adequate delimitation of the orebody can improve the mining selectivity, leading to greater income. Finally, a study of the increase in mining cost that provides a zero difference in NPV between the different block size options is carried out, in order to determine the maximum increase in mining costs for which it remains profitable to mine at a smaller block size.
Keywords: Mining selectivity, support effect, block boundary dilution, selective mining unit size, block model.

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