The Wallace miner. [volume] (Wallace, Idaho) 1907-current, 1912-10-31
VALUE OF S|DER|7E
TA|u|NGS FOR ROAD
BUILDING SET FORTH
SHosHoNE COUNTY MINING EN-.
GINEER WRITES ARTICLE.
SHOWING RESULTS.
Waste From the Mills May Be Util.
lied and Prove One Of the Best
Materials to Be Found, as Expert
ence Has Shown.

The following interesting and in
structive article, written by George
Huston, mining engineer, of Mullan,
appears in the current number of
Mining Science, published in Denver;
There are two important consider
atoms confronting the road builder
today.
First--How to more fully utilize the
local materials for road building.
Sacond-To secure more definite
knowledge as to the character and be-
hayior of such local materials.
OF course there are other things to
be studied, relating to maintenance
and administration, but this can be
treated later.
In the zinc districts of Missouri, the
county roads are unexcelled for their
smoothness and ease of upkeep. This
is rendered possible by the use Of the
mill tailings, commonly called chats"
which are at once hard and tough the
dust resulting from surface wear fur
.nishing the binder when wetted to
cement the particles underneath.
Tailings enter into road building to
a large extent in the Occur d'Alene
region, but 1t is of a different charac-
ter. We have no limestone in con-
nection with our ore deposits.
The waste from the mills falls into
two classes:
First-Silicious, brittle rock, con-
sisting of quartz material.
Second-Iron minerals, such as sid
erite, with much less amount of
pyrite and also in some localities,
magnetic.
The failing from the Canyon creek
mines Is mainly of the siliclous rock
class. The mills are situated In Wal
lace or near and this material has
been largely used for street and road
work in that town.
The waste from the Mullan mines
Is principally the iron minerals with
some magnetic and silicious matter.
The Larson mill of the Snowstorm
mine outputs a purely silicious pro-
duet OF the Wardner- Kellogg prop
critics. the Bunker Hill and Sullivan
turns out siderite thing, that of the
Last Chance mill being of the same
al, ,t
material than it's big neighbor. The
Stewart mine ore is milled at Wal
lace. 1t has soft, decomposed rock
for gangue, totally unsuited for road
work. The Success mine up Nine
Mile creek from Wallace has a mag
netite iron gangue with considerable
quartzose matter. Some portions of
our roads have been top dressed with
silicious rock from old mine dumps
but this has not proven very salts
factory,
Experience is showing that there is
a vast degree of difference in the be-
havior of the two classes when used
on roads or streets.
The silicious rock material is hard.
brittle and of low specific gravity. 1t
grinds fine easily under the pressure
of heavy wheel traffic, mixing me-
chemically with water to form mud. 1t
has no natural cement consequently
when dry the mud becomes dust,
which rises in clouds from the swift
moving wheels. Under the suction of
the rapidly revolving automobile tire,
the dust and small particles being
light and having no cementing bind
err to hold them down, are lifted from
the road surface, leaving it full of
ruts. During the spring and fall
months and after heavy rains. the
water tends to stand and mud and
ruts are much in evidence.
Using an artificial binder, such as
tar or bitumen, would be expensive
and inefficient. The silicious failing
is brittle, not possessing that degree
of toughness which is prime requi-
site for such a binder. while oiling is
hardly likely to better the dust situa
ton.
Experience with the silicious rock
failing shows conclusively that 1t
leaves much to be desired in point Of
upkeep and comfort in
1t must be admitted that we have
not had as much experience with the
iron tailings as with the other class,
but although the study has been
and incomplete, enough
has been learned to show that its use
will give more satisfactory road ma
.erial.
The principal material involved Is
,iderite, the carbonate Of iron, con-
,isting, when pure, Of iron oxide 62.l
ser cent, carbonic acid S7.S per cent,
Il with metallic iron content Of
|s.2 per cent. When pure the mineral
J brittle, but admixed substances In
his region give 1t certain degree Of
f nJ