Blackfoot news. (Blackfoot, Idaho) 1891-1902, 1899-10-28
BENEFITS OF CONCENTRATION.
-" important nrAnch Of MetAliurxy That
II Sometimes Overlooked.

u
II Sometimes Overlooked.
One of the most important branches
10 The netallurgical field OF the min
nie industry Is that OF concentration
III many districts too little attention Is
paiu 10 H. Ores are shipped In bulk.
or are rudely hand sorted and the best
P"r'ioh shipped 10 the shelters at
proht, II Il true, but at greater cost
.hah would he necessary II concenira-
non by mechanical means were first
eiupioyed. The second grade ores re-
main ON the dump in many cases, prac-
ucaiis waste, though containing good
values. In some mines the ores are
80 disseminated through the gangue
thht hand sorting can Ike carried ON
rapidly and economically. but this Is
Only The ease where the ore occurs in
considerable masses. Hand sorting tx
not economically practicable when the
mineral occurs In the form OF dissent
nared grains.
Concentrating machinery Is designed
Tor specific purposes, but has consider
able range of application. Most ores
are easily concentrated nj low cost, but
some complex ores. such ms those con
thinning an intimate mixture OF pyrite
galena and blende. afford unsatisfac-
tory results. Fortunately. the latter
class of ores do not occur universally.
though found In large quantity In some
mining regions. Generally plant
consisting Of rock breakers. rolls,
iroiDmeis. jigs and concentrating Ia
bles. buddles or bell machines are bet
ter adapted 10 concentrating ores than
stamps and concentrating machine s
alone, for the reason that large per-
ceniage OF the mineral Is obtained
In the first parts OF the operation. the
particles being comparatively coarse.
the fine material being collected I'm the
latter part OF the process. Stamps
crush all portions SO fine that the sub
segment recovery of the smallest par
/ ticles. which Ia some ores crushed by
stamps form the largest portion OF the
valuable mineral, becomes "A matter OF
great difficulty. Rolls create a more
I uniform product. ms they have ten
7 censy 10 crack and not To grind tho
/ ore. and as most sulphIde minerals
break along the lines OF their natural
/ cleavage when subjected TO crushing
force. the small grains have angular
I faces which seem 10 facilitate their
separation from the gangue. II Is the
Z aim of the successful concentration 10
I make as few shines ms possible.
When ores high grade enough TO shir
I without sorting are concentrated by
machinery. the gangue. II containing
7 values Ia gold and silver. may be sepa
rately treated subsequently by anal
ramation or some teaching process. II
I they viii not pay for this subsequent
( manipulation they certainly will moi
pay the transportation and reduction
charges when shipped TO the smelter
II Is mistake which many miners
make 20 send poor ore with rich. ever
though the average he high. for II The
poor alone viii not pay. IL pays no bet
ter when mingled with the bigh-grads
ore. This Il a simple proposition which
seems 70 b. lost sight Of ~ the desire
20 secure quantity. IN shipping ore,
the aim should be 20 get as high vain,
rs possible In as small bulk as posi-
. BILE Mining aud Scientific Press.