Grange. — Geology of Green Island Coalfield. 



173 



" Only one sample was forwarded by the Inspector of Mines, but ss 

 this appeared to have been taken from two different seams it was divided 



into two samples. 



Analysis. 

 Silica (Si0 2 ) .. 

 Alumina (A1 2 3 ) 

 Iron oxide (Feo0 3 ) 

 Titanium dioxide (TiOo) 

 Lime (CaO) . . 

 Magnesia (MgO) 

 Soda (Na 2 0) . . 

 Potash (K 2 0) 

 Water at 100° C. (H 2 0) 

 Combined water and organic matter 



Feldspar 



Quartz 



Clay substance 



Rational Analysis 



" Small briquettes and tiles were made from the samples, and the physical 

 tests on these showed that good bricks and tiles could be obtained between 

 the temperatures 1050° and 1100° C. At 1140° C. the bricks and tiles 

 showed distinct signs of overburning. The porosity of small tiles made at 

 ] 060° C. appeared quite satisfactory. 



Temp. 



c. 



Air 

 Shrinkage. 



Water- 

 absorption, 

 Shrinkage. Three Days 



Total 



Colour. 



Hardness. 



Remarks. 



13-22 



15-88 

 1-78 



No. 1. 

 Red . . 



Dark red 



Easily moulded. 

 Scratch with file Good brick. 



Very dark Completely vitrified 

 red 



No. 2. 



Slightly oyer- 

 burned. 



" Microscopically the samples showed the following composition : — 

 " No. 1. — Large irregular crystals of iron-stained quartz. No free, crystals 

 of magnetite or rutile, but the quartz in some cases penetrated by capillary 

 or acicular crystals of what appears to be rutile. Feldspar plentiful ; some 

 fairly elongated crystals. 



" No. 2. — Not quite so coarse in texture as No. 1, and not so much iron- 

 stained quartz. A little magnetite and a few crystals of rutile. Feldspar 

 plentiful and elongated." 



A large brick-kiln was erected by Gray, of the Fernhill Colliery ; but 

 the clay, besides containing a great number of boulders, was found to be 

 unsuitable for brickmaking. Bricks were made some years ago from a 

 bed, about 15 ft. thick, near the Walton Park shaft. 



