Rock works

To meet the extraordinary conditions existing in this deposit, said he, I decided that the only way to mine this sulphur was to melt it in the ground and pump it to the surface in the form of a liquid.. .. At that time, the drilling of a well in an alluvial deposit containing quicksand, etc., was a very tedious task, and it took from six to nine months to get through the alluvial material to the rock-work which we do today in three days.. . . When everything was ready to make the first trial,... 

These mixtures, however, brought no new advantages and did not fully meet requirements with regard to safety in gassy and dusty mines, sensitiveness to impact and friction and mining efficiency. In addition, perchlorate explosives, like chlorate ones, have the defect that under certain conditions they do not detonate, but burn out in the shothole, which may lead to a catastrophic fire or explosion. Perchlorate explosives were then withdrawn from coal work after World War I and restricted exclusively to rock work. Japan seems to be the only country where some perchlorate explosives are accepted as permitted explosives (see p. 474). 

The addition of aluminium to increase the heat of the explosion and, in consequence, the power of the explosive, as practised for some time, is now believed to be too dangerous. Ammonium nitrate explosives with aluminium are permitted only for rock work in opencast mining (e.g. quarries) or underground, where there is no methane. 

Type II—explosives which, when a 1400 g charge is fired in a steel mortar in an experimental gallery, fail to ignite a 9% methane-air mixture or coal-dust. They are used with an inert sheath in rock workings. Their rate of detonation is about 3300 m/sec (charge 30 mm dia.) at a density of 1.1, their transmission distance 6 cm. 

Ingredients Explosifs couche (for coal work) Explosifs roche (for rock work only) ... 

III) Approved for rock work in gassy and dusty mines ... 

Destructive test and field test of coal rock work is often restricted with problems, the coupling of methane gas and coal rock solid during the coal rock rupture process is still difficult to resolve now. In this paper, acoustic emission and coal rock damage are combined to do some research based on the analysis of laboratory data, the following conclusions may be get ... 

The rock work cost saving, specifically for the additional winze production hoisting compartment, would represent approximately 4.0M. 

By 1980, research and development shifted from relatively inexpensive surfactants such as petroleum sulfonates to more cosdy but more effective surfactants tailored to reservoir and cmde oil properties. Critical surfactant issues are performance in saline injection waters, adsorption on reservoir rock, partitioning into reservoir cmde oil, chemical stabiUty in the reservoir, interactions with the mobiUty control polymer, and production problems caused by resultant emulsions. Reservoir heterogeneity can also greatly reduce process effectiveness. The decline in oil prices in the early 1980s halted much of the work because of the relatively high cost of micellar processes. 

In the 1990s, the thmst of surfactant flooding work has been to develop surfactants which provide low interfacial tensions in saline media, particularly seawater require less cosurfactant are effective at low concentrations and exhibit lower adsorption on rock. Nonionic surfactants such as alcohol ethoxylates, alkylphenol ethoxylates (215) and propoxylates (216), and alcohol propoxylates (216) have been evaluated for this appHcation. More recently, anionic surfactants have been used (216—230). 

Fig. 12. The relationship between the mean oceanic residence time, T, yr, and the seawater—cmstal rock partition ratio,, of the elements adapted from Ref. 29. , Pretransition metals I, transition metals , B-metals , nonmetals. Open symbols indicate T-values estimated from sedimentation rates. The sohd line indicates the linear regression fit, and the dashed curves show the Working-Hotelling confidence band at the 0.1% significance level. The horizontal broken line indicates the time required for one stirring revolution of the ocean, T. ...

D-O SiphonSizerThe D-O SiphonSizer (Fig, 19-25) is a high-efficienev hvdraiilic classifier developed originally for the washing and sizing of phosphate rock. In ore-dressing work it is normally a two-prodiict unit but bv use of an upper column sealed at the top and... 

Grindabihty of phosphate rocks from different areas varies widely in Table 20-31 typical work-index data are shown. 

Rock type Calcium phosphate content, % Work index, kw.-hr./ton... 

Boron is comparatively unabundant in the universe (p. 14) it occurs to the extent of about 9 ppm in crustal rocks and is therefore rather less abundant than lithium (18 ppm) or lead (13 ppm) but is similar to praseodymium (9.1 ppm) and thorium (8.1 ppm). It occurs almost invariably as borate minerals or as borosilicates. Commercially valuable deposits are rare, but where they do occur, as in California or Turkey, they can be vast (see Panel). Isolated deposits are also worked in the former Soviet Union, Tibet and Argentina. 

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