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The Raise Boring of Large Diameter (>7.0mØ )Vertical Shafts on a South African Colliery
Greg Tr ive t t ,Sen io r P ro jec t Eng inee r, P ro jec t s and Techno logy Se rv ices ,
Saso l Min ing ,
S Y N O P S I S
A r e q u i r e m e n t w a s i d e n t i f i e d a t S a s o l M i n i n g t o h a r n e s s t h e c o s t ,s a f e t y a n d t i m e a d v a n t a g e s a s s o c i a t e d w i t h r a i s e - b o r i n g a s a s h a f ts inking method wi th the ever increas ing requirements for vent i la t ionv o l u m e .
P r e v i o u s l y a m a x i m u m d i a m e t e r o f 6 . 1 m e t e r s h a d b e e n r a i s e b o r er e a m e d ; t h i s a l l o w e d f o r a m a x i m u m a i r v o l u m e o f a l i t t l e o v e r560 m3/s for a s ingle ra ise bored upcas t shaf t . Sasol Mining requiredu p c a s t v e n t i l a t i o n i n s t a l l a t i o n s o n t w o o f i t s C o l l i e r i e s , w h i c hc o u l d e a c h d e l i v e r i n t h e r e g i o n o f 7 6 0 m 3 / s .
S i m p l y p u t , t h e s o l u t i o n f o r t h i s r e q u i r e m e n t w a s t o e i t h e r r a i s ebore two sha f t s , execu te a b l a s t ing ope ra t ion o r move the boundaryf o r r a i s e b o r i n g d i a m e t e r t o a t l e a s t 7 . 0 m .
S a s o l M i n i n g ( P t y ) L t d a n d R u c b o r ( P t y ) L t d h a v e s u c c e s s f u l l yc o n c l u d e d t h e r a i s e b o r i n g o f t h r e e s h a f t s a t > 7 . 1 m e t e r s d i a m e t e ra s pa r t o f a s equence o f n ine new sha f t s on Saso l Min ing ' s SecundaC o l l i e r i e s .
T h i s p a p e r d i s c u s s e s t h e p l a n n i n g a n d e x e c u t i o n o f t h e s e t h r e ela rge d iamete r shaf t s , pa r t i cu la r re fe rence i s made to the p reva i l ingl o c a l g e o l o g i c a l c o n d i t i o n s a n d t o t h e r i s k m i t i g a t i o n m e t h o d se m p l o y e d t o e n s u r e t h a t t h i s t e c h n o l o g y, - s t r e t c h i n g p r o j e c t w a sc o m p l e t e d s u c c e s s f u l l y.
" R i s k s e x i s t s , a n d t h e s u c c e s s f u l m i n i n g e n g i n e e r i s t h e o n e w h on e v e r a c c e p t s a s o l u t i o n a t f a c e v a l u e , h e s t r i v e s c o n t i n u o u s l yt o l e a r n f ro m t h e p a s t a n d t h e p re s e n t a n d h e i s a l w a y s p re p a redt o s o w h i s k n o w l e d g e i n t o t h e f u t u re " .
373
INT
RO
DU
CT
ION
Thi
s pa
per
to s
erve
s to
doc
umen
t th
e ge
neri
c as
wel
l as
spe
cifi
cin
vest
igat
ive,
des
ign,
pla
nnin
g an
d co
ntro
l w
ork
that
was
und
erta
ken
duri
ng t
he v
ario
us p
roje
ct p
hase
s fo
r th
e es
tabl
ishm
ent
of t
hree
larg
e di
amet
er (
> 7
.0m
∅)
rais
e bo
red
shaf
ts f
or S
asol
Min
ing
atit
's S
ecun
da c
ompl
ex.
The
Secu
nda
com
plex
Sas
ol M
inin
g ha
s op
erat
ions
at
Sas
olbu
rg a
nd S
ecun
da;
the
Sec
unda
oper
atio
ns c
onsi
st o
f th
e se
ven
full
y un
derg
roun
d m
ines
and
the
Syfe
rfon
tein
com
bine
d st
rip
and
unde
rgro
und
oper
atio
n. T
he c
ombi
ned
outp
ut f
rom
the
Sec
unda
min
es i
s 41
mil
lion
ton
s pe
r an
num
.
Bra
ndsp
ruit
, B
osje
sspr
uit,
Mid
delb
ult
and
Syf
erfo
ntei
n C
olli
ers
supp
ly g
assi
fica
tion
coa
l to
the
Sas
ol S
ynth
etic
Fue
ls (
SS
F)
plan
tat
Sec
unda
; T
wis
tdra
ai C
entr
al M
ine
prod
uces
bot
h ga
ssif
icat
ion
and
expo
rt q
uali
ty c
oal
and
the
Tw
istd
raai
Eas
t an
d W
est
min
esar
e de
dica
ted
expo
rt c
oal
prod
ucer
s.
Infr
astr
uctu
re u
pgra
de r
equi
rem
ents
for
ven
tila
tion
, sa
fety
and
logi
stic
al r
easo
ns r
esul
ted
in S
asol
Min
ing
esta
blis
hing
nin
e ne
wve
rtic
al v
enti
lati
on s
haft
s be
twee
n Ju
ne 2
000
and
July
200
1.
•T
wis
tdra
ai C
entr
al C
olli
ery:
1 of
f 6.
1m ∅
dow
ncas
t(D
/C),
125m
dee
p, e
quip
ped
wit
h es
cape
lad
der.
•M
iddl
ebul
t C
olli
ery:
1 of
f 7.1
mØ
upc
ast s
haft
,85
, d
eep
1 of
f 8.
6m ∅
dow
ncas
tsh
aft
equi
pped
for
man
and
mat
eria
ltr
ansp
ort.
•B
osje
sspr
uit
Col
lier
y:1
off
7.1m
∅ u
pcas
t ha
ft,
176m
dee
p1
off 7
.1m
∅ d
/cas
t sha
ft,
176m
dee
p
374
•S
yfer
font
ein
Col
lier
y:1
off
5.1m
∅ u
pcas
t sha
ft,
111m
dee
p1
off
4.1m
∅ d
ownc
ast
shaf
t, 1
05m
dee
p
•B
rand
spru
it C
olli
ery
1 of
f 4.8
m∅
upc
ast s
haft
,14
5m d
eep
1 of
f 5.
5m ∅
dow
ncas
tsh
aft,
145
m d
eep.
Pro
ject
pre
-fea
sibi
lity
and
fea
sibi
lity
stu
dy i
nves
tiga
tion
s ha
dde
term
ined
tha
t ra
ise-
bori
ng a
s a
shaf
t si
nkin
g ex
ecut
ion
met
hod
was
the
pre
ferr
ed t
echn
o-ec
onom
ic s
olut
ion.
The
refo
re t
hese
9 s
haft
s ar
e ra
ised
bor
ed a
nd s
hot-
cret
e li
ned
wit
h th
e ex
cept
ion
of t
he M
iddl
ebul
t m
an a
nd m
ater
ial
shaf
t w
hich
was
rai
se b
ored
to
3.8m
∅,
slip
ed t
o 9.
2m ∅
and
con
cret
e li
ned
to f
inal
dia
met
er (
8.6m
) as
req
uire
d fo
r th
e pe
rman
ent
hois
ting
equi
pmen
t.
Pro
ject
s an
d Te
chno
logy
Ser
vice
s (P
& T
S)
Thi
s de
part
men
t, a
div
isio
n of
Sas
ol M
inin
g i
s ba
sed
in S
ecun
daan
d pr
ovid
es a
ful
l P
roje
ct M
anag
emen
t an
d E
ngin
eeri
ng T
echn
ical
serv
ice
to t
he S
asol
Min
ing
oper
atio
ns.
P&
TS
wer
e ap
poin
ted
proj
ect
man
ager
s fo
r th
ese
shaf
t pr
ojec
tsan
d ac
cept
ed r
espo
nsib
ilit
y fo
r al
l en
gine
erin
g, p
rocu
rem
ent
and
cons
truc
tion
man
agem
ent
func
tion
s (E
PC
M),
as
wel
l as
the
sta
tuto
ryre
spon
sibi
liti
es.
Ruc
bor
(Pty
) L
td,
a di
visi
on o
f R
UC
min
ing
wer
e ap
poin
ted
asra
ise
bor
ing
cont
ract
ors
wit
h R
ucm
in (
Pty
) L
td e
xecu
ting
the
slip
ing,
lin
ing
and
equi
ppin
g op
erat
ions
at
the
Mid
dleb
ult
man
and
mat
eria
l sh
aft.
Pie
k M
inin
g (P
ty)
Ltd
wer
e aw
arde
d th
e co
ntra
ct t
o bo
lt,
mes
han
d sh
ot-c
rete
lin
e th
e re
mai
nder
of
the
shaf
ts.
Per
cuss
o B
or (
Pty
) L
td e
xecu
ted
the
pre-
min
ing
grou
nd s
tabi
lisa
tion
wor
k at
the
Bos
jess
prui
t sh
afts
.
375
LA
RG
E H
OL
E R
AIS
E B
OR
ING
-
A T
EC
HN
OL
OG
YIN
SIG
HT
.
Sas
ol M
inin
g ha
s ha
d pr
evio
us e
xper
ienc
e w
ith
rais
e bo
ring
in
the
Hig
hvel
d C
oal f
ield
. An
unde
rsta
ndin
g of
the
geol
ogic
al c
ondi
tion
san
d th
e ef
fect
the
se c
ondi
tion
s ha
ve o
n a
rais
e bo
ring
ope
rati
onar
e a
pre-
requ
isit
e fo
r su
cces
sful
pro
ject
exe
cuti
on.
The
rai
se b
orin
g te
chno
logy
, eq
uipm
ent
and
oper
atio
nal
met
hods
to b
e us
ed h
ave
to b
e un
ders
tood
in
orde
r to
car
ry o
ut t
he m
inin
gde
sign
and
ass
essm
ent
of r
isk.
The
se r
isk
asse
ssm
ents
mus
t ta
ke i
nto
cons
ider
atio
n th
e m
echa
nica
lpe
rfor
man
ce o
f th
e ra
ise
bori
ng e
quip
men
t as
wel
l as
the
pre
vail
ing
min
ing
and
geol
ogic
al c
ondi
tion
s.
The
tec
hnol
ogy
for
the
smal
ler
diam
eter
(up
to
the
6.1m
∅ r
equi
red
at T
wis
tdra
ai)
rais
e bo
ring
ope
rati
ons
was
ope
rati
onal
ly p
rove
nan
d st
anda
rd r
eam
ing
tool
s w
ere
avai
labl
e.
A d
iam
eter
of
6.1m
was
how
ever
insu
ffic
ient
for
the
vent
ilat
ion
requ
irem
ents
at M
iddl
ebul
tan
d B
osje
sspr
uit
Col
lier
s.
Opt
ing
for
eith
er a
dua
l ra
ise
bore
d sh
aft
syst
em o
ptio
n or
an
alte
rnat
ive
min
ing
met
hod
was
not
cos
t ef
fect
ive
and
Sas
ol M
inin
gre
ques
ted
that
Ruc
bor
inve
stig
ate
the
pote
ntia
l of
rea
min
g to
gre
ater
than
6.1
m ∅
wit
h an
obj
ecti
ve o
f ac
hiev
ing
±7m
.
Ruc
bor
wer
e su
cces
sful
in
achi
evin
g te
chni
cal
solu
tion
s fo
r th
eir
equi
pmen
t re
quir
emen
ts,
and
alth
ough
thi
s m
echa
nica
l de
sign
sti
llha
d to
be
oper
atio
nall
y pr
oven
, em
bark
ed o
n th
is p
roje
ct w
ith
Sas
ol M
inin
g. R
isk
mit
igat
ion
in t
his
rega
rd i
s di
scus
sed
late
rin
thi
s pa
per
.
Add
ress
ing
the
oper
atio
nal
risk
s as
soci
ated
wit
h th
e si
te s
peci
fic
min
ing
cond
itio
ns r
equi
red
deta
iled
inf
orm
atio
n on
the
in
situ
stra
ta c
ondi
tion
s as
wel
l as
an
unde
rsta
ndin
g of
how
the
rel
evan
tst
rata
wou
ld r
eact
und
er r
eam
ing
and
expo
sed
(rap
id w
eath
erin
g)co
ndit
ions
.
GE
OL
OG
ICA
L C
ON
DIT
ION
S
Gen
eral
geo
logy
376
The
Kar
oo s
uper
grou
p se
dim
ents
in
the
Hig
hvel
d C
oal
fiel
d ar
ere
pres
ente
d fr
om t
he b
ase
upw
ard
by t
he D
wyk
a fo
rmat
ion,
the
Pie
term
arit
zbur
g fo
rmat
ion,
the
Vry
heid
for
mat
ion
and
part
iall
yth
e V
olks
rust
for
mat
ion
of t
he E
cca
Gro
up.
The
sed
imen
ts r
ange
thr
ough
coa
l, m
udst
ones
, sil
tsto
nes,
san
dsto
nes,
grit
s an
d ti
llit
es.
Dol
erit
ic d
ykes
and
sil
ls r
elat
ed t
o th
e st
orm
berg
lava
s ex
tens
ivel
y in
trud
e th
e co
alfi
eld.
(A
dden
dum
1)
The
por
tion
of
inte
rest
to
the
rock
eng
inee
r an
d sh
aft
sink
ing
proj
ect
plan
ner
at S
ecun
da C
olli
ers
is t
he p
orti
on o
f th
e st
rati
grap
hyfr
om t
he N
umbe
r 4
Low
er C
oal
Sea
m t
o th
e su
rfac
e. T
here
are
anu
mbe
r of
asp
ects
tha
t af
fect
the
cre
atio
n of
an
exca
vati
on i
nth
is g
roun
d, t
hese
are
:
•T
he w
ide
disp
arit
y of
Uni
axia
l co
mpr
essi
ve s
tren
gths
, fr
om7M
pa f
or C
oal
to >
250M
pa f
or t
he m
ore
com
pete
nt d
oler
ites
.
•T
he r
eact
ion
of i
ndiv
idua
l ro
ck t
ypes
on
oxid
atio
n, t
he r
ocks
wit
h hi
gh c
lay
cont
ent
tend
to
wea
ther
pre
fere
ntia
lly
resu
ltin
gin
neg
ativ
e pr
ofil
es o
n th
e ex
cava
tion
.
•T
he d
isti
nct
join
ting
set
s in
the
Dol
erit
e w
ith
the
prin
cipa
ldi
rect
ions
at
900
to e
ach
othe
r in
the
ver
tica
l ax
is a
nd a
thir
d jo
inti
ng s
et i
n th
e ho
rizo
ntal
axi
s re
sult
ing
in b
lock
ygr
ound
.
The
ove
rbur
den
of t
he N
umbe
r 4
Low
er C
oal
Sea
m c
an b
e cl
assi
fied
as a
seq
uenc
e of
upw
ard
coar
seni
ng s
edim
enta
ry u
nits
eac
h ca
pped
by a
coa
l ho
rizo
n th
at i
s ty
pica
l of
pro
grad
ing
delt
aic
sequ
ence
s.
Spec
ific
geo
logy
: M
iddl
ebul
t an
d B
osje
sspr
uit
(7.1
mØ
) sh
afts
The
dis
pari
ty o
f th
e un
iaxi
al c
ompr
essi
ve s
tren
gths
was
les
s ev
iden
tat
Mid
dleb
ult
whe
re t
he s
haft
col
lar
is s
itua
ted
stra
tigr
aphi
call
ybe
low
the
Num
ber
4 D
oler
ite
sill
(B
4) a
nd t
he N
umbe
r 8
Dol
erit
esi
ll (
B8)
doe
s no
t in
ters
ect
the
shaf
t po
siti
on.
The
Mid
delb
ult
shaf
t pr
esen
ted
a lo
w g
eolo
gica
l/m
inin
g ri
sk p
rofi
le.
The
sit
uati
on a
t B
osje
sspr
uit
is h
owev
er q
uite
dif
fere
nt,
both
the
B4
and
B8
sill
s ar
e pr
esen
t at
bot
h sh
aft
posi
tion
s. (
Add
endu
m2) 37
7
The
B8,
alt
houg
h ve
ry h
ard
by k
aroo
seq
uenc
e st
anda
rds
was
wel
lbe
low
the
har
dnes
s of
>45
0 M
pa U
CS
mat
eria
l fr
eque
ntly
enc
ount
ered
duri
ng r
aise
-bor
ing
oper
atio
ns o
n S
outh
Afr
ica'
s pl
atin
um m
ines
.In
add
itio
n, t
his
stra
ta h
as b
een
succ
essf
ully
pil
oted
and
rea
med
seve
ral
tim
es a
t S
ecun
da.
The
str
atif
icat
ion
of t
he B
4 do
leri
te s
ill
was
kno
wn
from
ear
lier
shaf
t pr
ojec
ts t
o pr
esen
t ra
ise
bori
ng c
hall
enge
s, t
he r
easo
ns f
orth
is a
rea
cove
red
in t
he n
ext
sect
ion.
The
Num
ber
4 do
leri
te s
ill
at B
osje
sspr
uit
is c
over
ed b
y 15
met
res
of s
emi-
wea
ther
ed t
o w
eath
ered
ove
r bu
rden
and
has
thr
ee m
ajor
lith
olog
ical
uni
ts:
•T
he l
ower
uni
t is
a 1
0met
res
thic
k fi
ne t
o m
ediu
m c
ryst
alli
negr
anul
ar d
oler
ite
wit
h m
inor
non
-ori
ente
d fe
ldsp
ar l
aths
.It
is
a co
mpe
tent
uni
t w
ith
sem
i ve
rtic
al j
oint
ing
wit
h a
90º
angl
e be
twee
n th
e tw
o pr
inci
ple
join
t di
rect
ions
. T
hesp
acin
g be
twee
n th
e jo
ints
was
ass
esse
d to
be
± 1
.4m
(fi
gure
1).
The
re i
s al
so a
hor
izon
tal
join
ting
com
pone
nt,
the
vert
ical
spac
ing
here
was
det
erm
ined
to
be ±
1.0m
as
obse
rved
at
vari
ous
road
cut
ting
s in
the
Hig
hvel
d C
oal
fiel
d ar
ea.
•T
he n
ext
lith
olog
ical
uni
t, w
hich
is
appr
oxim
atel
y 12
met
res
thic
k co
nsis
ts o
f a
high
ly s
erpe
ntin
ized
fin
e to
med
ium
cry
stal
line
dole
rite
. T
his
unit
is
high
ly j
oint
ed h
oriz
onta
lly,
wit
h a
typi
cal
join
t sp
acin
g in
the
ord
er o
f 5
to 8
cen
tim
etre
s.T
his
unit
wea
ther
s ex
cept
iona
lly
quic
kly
(fig
ure
2).
•T
he u
pper
mos
t li
thol
ogic
al u
nit
is s
imil
ar t
o th
e lo
wer
mos
tun
it.
Thi
s un
it i
s 18
met
res
thic
k an
d ou
tcro
ps o
n su
rfac
ew
ith
the
uppe
r 10
met
res
bein
g hi
ghly
wea
ther
ed. T
he j
oint
ing
agai
n is
sim
ilar
to
the
low
erm
ost
unit
.
378
EX
EC
UT
ION
RIS
K I
DE
NT
IFIC
AT
ION
AN
D M
ITIG
AT
ION
AC
TIO
NS
.
Tab
led
belo
w a
re t
he m
ajor
exe
cuti
on r
isks
ide
ntif
ied
and
the
mit
gati
on a
ctio
ns u
nder
take
n.
Incr
ease
d sh
aft
diam
eter
(M
echa
nica
l ri
sk
379
Cha
llen
ging
geo
logi
cl c
ondi
tion
s (M
inin
g R
isk) Fi
gure
3
Figu
re 3
380
TE
CH
NIC
AL
SO
LU
TIO
NS
TO
RIS
K M
ITIG
AT
ION
RE
QU
IRE
ME
NT
S.
Ens
urin
g th
e m
echa
nica
l in
tegr
ity
of t
he r
aise
bor
ing
equi
pmen
t.(R
isk
1)
Ruc
bor
wer
e su
cces
sful
in
achi
evin
g te
chni
cal
solu
tion
s fo
r th
eir
equi
pmen
t re
quir
emen
ts,
thes
e in
clud
ed:
•T
he a
cqui
siti
on o
f th
e up
grad
ed d
rill
str
ing
requ
ired
for
the
add
itio
nal
torq
ue r
equi
rem
ents
.
•T
he d
esig
n of
ext
ensi
on w
ings
to
be f
itte
d to
a s
tand
ard
6.1m
∅ r
eam
er h
ead
base
and
,
•T
he c
onfi
gura
tion
of
the
ream
ing
cutt
ers
on t
his
exte
nded
ream
er h
ead
to a
chie
ve a
rea
med
dia
met
er o
f 7.
1m.
The
res
ult
was
a r
eam
er h
ead,
whi
ch w
ould
ena
ble
the
exca
vati
onof
the
req
uire
d 7.
1m∅
sha
fts
thro
ugh
the
stra
ta o
verl
ying
the
shaf
t po
siti
ons
at t
he M
idde
lbul
t an
d B
osje
sspr
uit
vent
ilat
ion
shaf
ts.
Act
ions
pri
or t
o ra
ise
bori
ng (
Pre
-min
ing
grou
nd s
tabi
lisa
tion
)
Sta
bil
isat
ion
of
cen
tre
core
for
pil
ot h
ole
dri
llin
g(R
isk
2)
The
fir
st r
equi
rem
ent w
as to
rep
lace
the
uppe
r te
n m
etre
s of
wea
ther
edm
ater
ial i
n th
e sh
aft c
entr
e to
a d
iam
eter
that
wou
ld s
afel
y ac
com
mod
ate
the
381
mm
Ø p
ilot
hol
e. T
his
was
ach
ieve
d by
dri
llin
g a
600m
mø
and
back
fil
ling
wit
h 30
Mpa
mas
s co
ncre
te p
rior
to th
e es
tabl
ishm
ent
of t
he r
aise
-bor
ing
cont
ract
or.
Var
ious
dri
llin
g op
tion
s ar
e av
aila
ble,
inc
lude
d th
e C
ham
ber
ofM
ines
res
cue
dril
l an
d pi
ling
aug
er r
igs.
Due
to
tim
e, s
afet
y an
dlo
gist
ical
con
stra
ints
at
the
tim
e of
exe
cuti
on,
a bu
tton
bit
rea
mer
on a
per
cuss
ion
dril
l ri
g w
as u
sed
to w
iden
a 2
03m
m h
ole,
foa
mw
as a
dded
to
the
dril
l li
quid
to
ensu
re a
dequ
ate
flus
hing
of
the
dril
l ch
ips
wit
h th
e in
crea
sed
annu
lus
of t
he h
ole.
(F
igur
e 4)
381
The
sec
ond
requ
irem
ent
was
to
min
imis
e th
e am
ount
of
pilo
t ho
leer
osio
n in
the
mid
dle
zone
of
the
B4
dole
rite
. E
xten
ding
the
600
mm
ø ho
le t
o a
dept
h of
±50
m w
as u
nacc
epta
bly
cost
ly;
the
sele
cted
solu
tion
was
to
appl
y a
bent
onit
e m
ud a
ddit
ive
to t
he f
lush
ing
wat
er d
urin
g pi
lot
hole
dri
llin
g.
Sta
bil
isat
ion
of
ream
ing
face
(R
isk
3)
A c
olla
pse
or p
arti
al c
olla
pse
of t
he r
eam
ing
face
dur
ing
rod
chan
geou
t w
ill
resu
lt i
n co
stly
del
ays,
ens
urin
g th
at t
he f
ace
rem
ains
inta
ct i
s a
prer
equi
site
.
Sta
ndar
d st
rata
con
trol
pri
ncip
les
are
used
in
desi
gnin
g th
e lo
adbe
arin
g re
quir
emen
ts o
f an
y su
ppor
t sy
stem
em
ploy
ed.
The
rea
mer
fac
e su
ppor
t sy
stem
has
the
fol
low
ing
desi
gn d
rive
rs:
•T
he m
inim
um te
nsil
e fa
ilur
e st
reng
th o
f the
sup
port
s (d
owel
s)sh
ould
be d
eter
min
ed b
y th
e m
ass
of a
"bl
ock"
of
B4
dole
rite
, w
hich
pote
ntia
lly
coul
d ke
y ou
t of
the
rea
min
g fa
ce.
Mas
s=
V
olum
e S
.G=
1.
4m X
1.4
m x
1.0
m X
2.7
m t
ons/
m3
=
5.3
tons
•A
saf
ety
fact
or o
f 1.
1 w
as a
ppli
ed r
esul
ting
in
a te
nsil
e s
tren
gth
requ
irem
ent
of e
ach
supp
ort
dow
el o
f 58
.2 K
n.
•T
he d
owel
s sh
ould
hav
e sh
ear
stre
ngth
as
low
as
poss
ible
and
shou
ld d
efin
itel
y no
t in
clud
e an
y st
eel
so a
s no
t to
inte
rfer
e w
ith
late
r ra
ise
bori
ng o
pera
tion
s sh
ould
a h
ole
devi
ate
into
the
sha
ft.
•D
owel
spa
cing
sho
uld
ensu
re c
over
age
of th
e fu
ll s
haft
dia
met
erta
king
acc
ount
of
the
1.4m
spa
cing
of
the
vert
ical
joi
nts
in t
he B
4 D
oler
ite.
A 1
0mm
ø f
ibre
gla
ss r
einf
orce
d pl
asti
c ro
d w
ith
a sp
ecif
ied
tens
ile
stre
ngth
of
50K
n w
as s
ourc
ed;
thre
e ro
ds a
re u
sed
in e
ach
com
posi
tedo
wel
. T
wen
ty d
owel
s ar
e in
stal
led
in e
ach
shaf
t
382
Thr
ee t
est
dow
els
wer
e m
ade
up a
nd f
ailu
re t
este
d at
CS
IR M
inin
gT
ek w
ith
the
foll
owin
g re
sult
s:
Tes
t on
e-
Max
imum
loa
ds c
arri
ed =
61.6
Kn.
Tes
t tw
o-
Max
imum
loa
d ca
rrie
d =
71.3
Kn.
Tes
t th
ree
-M
axim
um l
oad
carr
ied
=58
.8 K
n.
Sta
bil
isat
ion
of
shaf
t si
de
wal
ls (
Ris
ks
4,5
and
6)
The
kno
wn
inst
abil
ity
of t
he u
pper
10m
wea
ther
ed o
verb
urde
nas
wel
l as
the
pro
pens
ity
of t
he f
riab
le a
nd r
abid
ly w
eath
erin
gm
iddl
e zo
ne o
f th
e B
4 D
oler
ite
to s
elf
min
ing
dict
ated
tha
t a
mea
ns b
e fo
und
to e
ffec
t th
e fo
llow
ing:
•S
truc
tura
lly
rein
forc
e th
ese
regi
ons
to n
egat
e th
e ef
fect
of
any
late
ral
forc
es o
n th
e sh
aft
side
wal
l/
•A
rres
t an
y ov
er m
inin
g th
at m
ay o
ccur
.
Not
e 1
Con
side
rati
on w
as g
iven
to
the
inje
ctio
n of
a r
esin
bas
ed m
atri
xin
to t
he w
eath
ered
are
as a
s w
ell
as t
he s
erpe
ntin
ised
dol
erit
e zo
ne,
the
idea
bei
ng t
hat
a co
nsol
idat
ed c
ore
roug
hly
the
diam
eter
of
the
shaf
t w
ould
be
crea
ted
whi
ch c
ould
the
n be
rea
med
. F
ield
tria
ls s
how
ed t
hat
a re
sin
mix
ture
inj
ecte
d th
roug
h a
76m
m ∅
hole
did
not
mig
rate
suf
fici
entl
y th
roug
h th
e st
rata
to
reac
h th
esh
aft
peri
met
er a
nd i
n fa
ct t
ook
the
shor
test
rou
te,
whi
ch w
asdi
rect
ly i
nto
the
feed
hol
e di
rect
ly a
bove
the
poi
nt i
njec
tion
.
Hig
h-pr
essu
re c
emen
t gr
outi
ng t
echn
olog
y co
uld
not
be a
ppli
ed,
as t
he n
atur
e of
the
str
ata
is n
ot c
ondu
cive
to
this
tec
hnol
ogy.
The
sol
utio
n op
ted
for
was
to
inst
all
a ri
ng o
f re
info
rced
"sp
iles
"ou
tsid
e th
e pe
rim
eter
of
the
shaf
t. E
ach
spil
e co
nsis
t of
a 2
50m
mø
vert
ical
hol
e dr
ille
d fr
om s
urfa
ce t
o be
low
the
B4
Dol
erit
e, a
50m
m∅
ste
el p
ipe
is i
nser
ted
alon
g th
e fu
ll l
engt
h of
the
hol
ean
d th
e ho
le i
s fu
ll c
olum
n ce
men
t gr
oute
d th
roug
h th
e pi
pe.
A t
otal
of
51 "
spil
es"
are
inst
alle
d ar
ound
eac
h sh
aft
at 5
00m
msp
acin
g be
twee
n ce
ntre
s, t
he n
et e
ffec
t is
a r
ing
of 2
50m
m ∅
rein
forc
ed c
oncr
ete
pile
s sp
aced
250
mm
apa
rt a
nd t
o a
dept
h of 38
3
60m
aro
und
each
sha
ft,
accu
racy
of
dril
ling
ver
tica
lity
was
clo
sely
mon
itor
ed.
The
int
egri
ty o
f th
is s
olut
ion
was
ver
ifie
d by
tes
ting
a d
esig
npr
opos
al b
y m
eans
of
num
eric
al m
odel
ling
, th
is w
ork
was
car
ried
out
by C
SIR
Min
ing
Tek
and
enta
iled
the
use
of
prop
riet
ary
soft
war
epr
ogra
ms.
The
des
ign
prop
osal
mod
elle
d in
clud
ed a
dou
ble
ring
of s
pile
s as
was
pro
pose
d fr
om p
revi
ous
expe
rien
ce.
Wha
t th
e m
odel
ling
sho
wed
was
tha
t a
sing
le r
ing
of s
pile
s w
assu
ffic
ient
; th
is r
esul
ted
in a
con
side
rabl
e co
st s
avin
g fr
om e
stim
ates
duri
ng t
he d
esig
n ph
ase.
Con
tin
uou
s op
erat
ion
in
B4
Dol
erit
e (R
isk
6)
Obs
erva
tion
of
the
serp
enti
sed
B4
zone
of
the
geol
ogic
al c
ore
(fig
ure
2) i
ndic
ated
tha
t se
vere
wea
ther
ing
of t
his
zone
wou
ldoc
cur
wit
hin
two
wee
ks o
f ex
posu
re t
o ai
r. T
his
mea
nt t
hat
the
serp
enti
ne i
n-fi
ll b
etw
een
dole
rite
joi
nts
wou
ld d
isap
pear
and
that
the
5 t
o 8
cent
imet
re j
oint
spa
cing
in
this
zon
e w
ould
res
ult
in r
apid
ly u
nrav
elli
ng s
trat
a.
Pla
nnin
g w
as i
n pl
ace
to a
pply
a l
ayer
of
shot
Cre
te t
o th
is z
one
as s
oon
as p
ossi
ble
afte
r ac
cess
cou
ld b
e ob
tain
ed t
o se
al t
hear
ea f
rom
the
atm
osph
ere
and
ther
efor
e ha
lt t
he w
eath
erin
g pr
oces
s.
The
exp
ecte
d ad
vanc
e of
the
rai
se b
orer
was
± 5
m/d
ay t
hrou
ghth
e B
4 D
oler
ite,
as
this
zon
e is
40-
50m
bel
ow s
urfa
ce i
t w
ould
take
at
leas
t 8
days
fro
m i
niti
al e
xpos
ure
of t
his
zone
to
com
plet
ion
of t
he r
eam
ing
oper
atio
n. R
eam
ing
oper
atio
ns t
here
fore
had
to
be c
onti
nuou
s on
ce t
he B
4 D
oler
ite
had
been
int
erse
cted
, fo
r th
isre
ason
cut
ter
and
ream
er m
aint
enan
ce w
as d
one
prio
r to
the
B4
bein
g re
ache
d.
Imm
edia
te r
emov
al o
f re
amer
an
d r
aise
bor
e eq
uip
men
t(R
isk
6)
For
the
sam
e re
ason
s as
not
ed a
bove
, re
mov
al o
f th
e re
amer
and
rais
e bo
ring
equ
ipm
ent
from
the
sha
ft s
houl
d ta
ke p
lace
wit
hin
24hr
s of
hol
ing.
Onc
e th
e re
amer
had
hol
ed t
o su
rfac
e th
is w
asac
hiev
ed b
y us
ing
a 55
0-to
n cr
ane
to f
irst
lif
t th
e 85
t ra
ise
bore
mac
hine
and
the
n th
e 10
5-to
n re
amer
hea
d. (
Fig
ures
5a.
& 5
b.)
384
Rap
id s
eali
ng
of B
4 d
oler
ite
(Ris
k 6
)
Now
tha
t th
e sh
aft
was
cle
ar o
f ra
ise
bori
ng e
quip
men
t a
laye
rof
sho
t-C
rete
was
app
lied
to
the
shaf
t si
dew
all.
The
req
uire
men
tsw
ere
as f
ollo
ws:
•A
pply
a 4
5mm
thi
ck s
eal
(fla
sh-c
oat)
to
the
shaf
t si
dew
all
from
the
col
lar
to a
dep
th o
f 60
m.
•E
nsur
e th
at t
he s
hot-
Cre
te w
ould
att
ain
a fi
nal
stre
ngth
of
35M
pa a
nd s
uffi
cien
t ea
rly
stre
ngth
tha
t w
ould
all
ow s
afe
acce
ss o
f w
orkm
en b
elow
new
ly a
ppli
ed s
hot
crea
te.
•C
ompl
ete
this
fla
sh-c
oat
wit
hin
72 h
rs o
f th
e re
amer
bei
ngre
mov
ed f
rom
the
sha
ft.
As
the
sche
dule
req
uire
men
ts p
recl
uded
any
sci
enti
fic
test
ing
ofsh
ot c
rete
for
log
isti
cal
reas
ons,
tri
als
wer
e co
nduc
ted
wit
h va
riou
sm
ixes
of
cem
ent
and
acce
lera
tors
, a
best
opt
ion
sele
cted
and
ast
anda
rd o
pera
ting
pro
cedu
re d
raw
n up
to
ensu
re t
he c
orre
ct a
ndsa
fe e
xecu
tion
of
this
ope
rati
on.
The
sho
t-cr
ete
was
a d
ry m
ix a
ppli
ed m
anua
lly
from
a b
osun
'sch
air.
Mix
and
wat
er w
ere
supp
lied
via
su
spen
ded
hose
s fr
omsu
rfac
e.
Fig
ure
6 is
a b
irds
eye
vie
w o
f th
e B
osje
sspr
uit
upca
st s
haft
pri
orto
the
ins
tall
atio
n of
the
sup
port
sta
ge a
nd t
empo
rary
acc
ess
syst
em.
B8
DO
LE
RIT
E A
NO
MA
LY
The
B8
dole
rite
has
nev
er b
een
the
caus
e of
any
fai
lure
or
non-
conf
orm
ance
at p
revi
ous
shaf
t sin
king
ope
rati
ons
at S
ecun
da. A
ltho
ugh
the
mat
eria
l, a
t 25
0-35
0 M
pa i
s ha
rd b
y K
aroo
seq
uenc
e st
anda
rds,
the
net
resu
lt o
f th
is h
ardn
ess
in a
rai
se b
orin
g op
erat
ion
is u
sual
lyli
mit
ed t
o a
slow
er a
dvan
ce r
ate
and
incr
ease
d cu
tter
wea
r.
The
B8
dol
erit
e w
as p
rese
nt a
s ex
pect
ed a
t bo
th t
he u
pcas
t an
ddo
wnc
ast
shaf
ts a
t B
osje
sspr
uit
Col
lier
y; a
t th
e up
cast
sha
ft,
whi
chw
as r
aise
bor
ed f
irst
, th
is d
oler
ite
was
enc
ount
ered
whe
re e
xpec
ted
385
and
man
aged
as
plan
ned.
At
the
dow
ncas
t sh
aft,
the
Dol
erit
e w
as e
xpec
ted
to b
e ±
12m
thi
ckas
per
a c
ore
hole
dri
lled
5m
fro
m t
he s
haft
per
imet
er,
inst
ead
this
int
rusi
on w
as w
edge
sha
ped
(Add
endu
m 3
) w
ith
a th
ickn
ess
vary
ing
betw
een
7.46
m a
nd 1
2.40
m o
ver
the
7.1m
dia
met
er o
fth
e sh
aft.
Thi
s an
omal
ous
situ
atio
n of
har
d (2
50 M
pa)
and
soft
(55M
pa)
mat
eria
l on
the
sam
e re
amin
g el
evat
ing
resu
lted
in
the
ream
er h
ead
bein
g pu
lled
off
lev
el a
nd t
he r
eam
er s
tem
fai
ling
caus
ing
the
ream
er t
o dr
op t
o sh
aft
bott
om.
The
loa
ding
sta
ndar
d op
erat
ing
proc
edur
e en
forc
ed e
nsur
ed t
hat
no p
erso
ns o
r eq
uipm
ent
wer
e at
ris
k w
hen
this
hap
pene
d. T
hene
t re
sult
was
a d
elay
of
six
wee
ks o
n th
e pr
ojec
t sc
hedu
le a
ndco
nsid
erab
le r
epai
r co
sts.
Thi
s ri
sk h
as b
een
mit
igat
ed i
n fu
ture
sha
fts
by d
rill
ing
core
sam
ples
fro
m f
our
posi
tion
s ar
ound
the
sha
ft,
a pr
acti
ce t
hat
isno
w s
tand
ard
proc
edur
e.
CO
NC
LU
SIO
N
•T
he c
ost,
saf
ety
and
sche
dule
adv
anta
ges
of r
aise
bor
ing
as a
sha
ft s
inki
ng m
etho
d ve
rtic
al v
enti
lati
on s
haft
s ar
ew
itho
ut q
uest
ion
for
the
cond
itio
ns p
reva
ilin
g at
Sec
unda
Col
lier
s.
•T
he te
chni
cal f
easi
bili
ty o
f th
e 7.
1m d
iam
eter
rea
min
g op
erat
ion
has
been
pro
ven,
les
sons
lea
rnt
wit
h th
e un
ique
con
diti
ons
expe
rien
ced
at t
he B
osje
sspr
uit
dow
ncas
t sh
aft
have
bee
nw
ell
docu
men
ted
and
the
requ
ired
add
itio
nal
mit
igat
ion
acti
ons
for
futu
re s
haft
pro
ject
s al
read
y in
stit
uted
.
•T
he p
roje
ct m
anag
er,
whe
n ap
proa
chin
g su
ch w
ork
whe
rene
w d
evel
opm
ent
and
sign
ific
ant
risk
s ar
e en
coun
tere
d m
ust
ensu
re th
at te
chni
call
y co
mpe
tent
con
trac
tors
, wit
h a
prof
essi
onal
atti
tude
are
app
oint
ed a
s pa
rtne
rs i
n th
e pr
ojec
t de
velo
pmen
t.
•A
gre
ater
app
reci
atio
n is
als
o he
ld f
or t
he n
eed
to m
anag
eou
t, w
here
pos
sibl
e, a
s m
any
assu
mpt
ions
and
geo
logi
cal
inte
rpre
tati
ons
base
d on
ass
umpt
ion
as p
ract
ical
ly p
ossi
ble.
386
It i
s a
stro
ngly
hel
d be
lief
tha
t ha
ving
det
aile
d in
form
atio
n on
the
prev
aili
ng g
eolo
gica
l an
d m
inin
g co
ndit
ions
, an
d be
ing
able
to s
ucce
ssfu
lly
synt
hesi
se t
his
know
ledg
e w
ith
the
oper
atio
n to
be u
nder
take
n is
a r
equi
rem
ent
for
succ
essf
ul p
roje
ct p
lann
ing
and
impl
emen
tati
on. T
he m
ore
com
plet
e th
e te
chni
cal i
nput
info
rmat
ion,
the
grea
ter
the
succ
ess
of t
he r
isk
mit
igat
ion
acti
ons
and
the
low
erth
e ri
sk o
f no
n-co
nfor
man
ce.
The
deg
ree
to w
hich
the
sha
ft s
inki
ng p
roje
ct m
anag
er i
s pr
epar
edto
inve
st in
the
acqu
isit
ion
of g
eo-t
echn
ical
and
geo
logi
cal i
nfor
mat
ion
has
to b
e ev
alua
ted
wit
h re
fere
nce
to t
he f
ollo
win
g fa
ctor
s.
•W
hat
prev
ious
exp
erie
nce
in s
imil
ar g
eolo
gica
l co
ndit
ions
have
bee
n su
itab
ly d
ocum
ente
d
•H
ow c
onsi
sten
t an
d un
ifor
m a
re t
he g
eolo
gica
l st
ruct
ures
in t
he a
rea?
i.e
. to
wha
t de
gree
can
ass
umpt
ions
be
mad
eon
spe
cifi
c co
ndit
ions
?
•H
as a
ll t
he t
echn
olog
y an
d eq
uipm
ent
to b
e em
ploy
ed b
een
oper
atio
nall
y pr
oven
?
Ult
imat
ely
thou
gh,
min
ing
rem
ains
as
alw
ays,
a s
cien
ce f
or t
hepr
agm
atic
.
"Ris
k ex
ists
, an
d th
e su
cces
sful
min
ing
engi
neer
is
the
one
who
neve
r ac
cept
s a
solu
tion
at
face
val
ue,
he s
triv
es c
onti
nuou
sly
to l
earn
fro
m t
he p
ast
and
the
pres
ent
and
he i
s al
way
s pr
epar
edto
sow
his
kno
wle
dge
into
the
fut
ure"
.
RE
FE
RE
NC
ES
Mod
elli
ng o
f su
ppor
t fo
r ve
ntil
atio
n sh
aft
at B
osje
sspr
uit
Min
e,D
P R
ober
ts e
t al
, C
SIR
div
isio
n of
Min
ing
Tec
hnol
ogy,
Nov
embe
r20
00.
Geo
tech
nica
l as
sess
men
t of
str
ata
cond
itio
ns a
nd c
omm
ents
on
supp
ort
desi
gn f
or v
enti
lati
on s
haft
s at
Cha
rl C
illi
ers,
Dr.
B.
Mad
den,
Dec
200
0.
387
The
rai
se b
orin
g of
lar
ge d
iam
eter
(>
7.0m
ø)
vert
ical
sha
fts
ona
Sou
th A
fric
an C
olli
ery,
Pre
sent
atio
n to
SA
CM
A,
G.
Tri
vett
,A
ugus
t 20
00.
Sas
ol M
inin
g, P
roje
cts
- G
eote
chni
cal
aspe
cts
of t
he s
inki
ng o
fsh
afts
in
the
Hig
hvel
d C
oalf
ield
, J.
Spa
rrow
, S
asol
Min
ing,
Mar
ch20
01.
AC
KN
OW
LE
DG
EM
EN
TS
The
aut
hor
ackn
owle
dges
and
giv
es t
hank
s fo
r th
e co
ntri
buti
ons
of t
he f
ollo
win
g co
llea
gues
.
For
the
ir c
onti
nued
tru
st a
nd e
ncou
rage
men
t:
Mes
srs.
Jan
nie
Van
Der
Wes
thui
zen,
Fri
k G
robb
elaa
r, J
acki
e V
ersl
uis,
Nic
o V
an E
ck,
Gar
y L
eibb
rand
t an
d Jo
han
Van
Zyl
of
Sas
ol M
inin
g.
For
the
ir t
echn
olog
y in
puts
:
To
Koo
s D
e be
er a
nd B
arne
y B
este
r fo
r th
eir
past
exp
erie
nces
in
rais
e bo
ring
at
Sec
unda
, D
awid
Pos
tma
and
Bri
an V
orst
er f
or t
heir
rock
eng
inee
ring
con
trib
utio
ns a
nd t
o Jo
hn S
parr
ow f
or h
is g
eolo
gica
lin
sigh
ts.
For
the
ir p
artn
ersh
ip r
oles
:
Coe
n R
oos,
Man
agin
g D
irec
tor,
Ruc
bor
(Pty
) L
tdIv
an W
alke
r, M
anag
ing
Dir
ecto
r, P
iek
Min
ing
(Pty
) L
tdP
iete
r P
reto
rius
, M
anag
ing
Dir
ecto
r, P
ercu
sso
Bor
(P
ty)
Ltd
Kal
li L
e R
oux
and
Roe
lf D
u P
reez
Ack
now
ledg
emen
t al
so t
o al
l th
e co
llea
gues
on
the
proj
ect
team
san
d on
the
min
es f
or t
heir
pro
fess
iona
lism
and
ded
icat
ion.
388
Fig
ure
1:
900
Ver
tica
l jo
inti
ng o
f B
4 D
oler
ite
•N
ote
cam
era
lens
cov
er f
or i
ndic
atio
n of
sca
le
389
Figure 2 :Serpen t in i sed zone in B4 Dole r i t e
• A l l t h e l i g h t e r, s e r p e n t i n e b a n d s i n t h i s c o r e d i s a p p e a r e d wi th in two weeks o f exposure to a i r r e su l t ing in a to t a l un rave l l ingo f t h i s 1 2 m t h i c k z o n e
• N o t i c e a l s o t h e v e r t i c a l f r a c t u r i n g p r e s e n t
390
Fig
ure
3:
Sha
ft c
olla
r re
ady
for
Rai
se b
ore
mac
hine
•N
ote
dow
els
and
spil
es c
ompl
eted
pri
or t
o ra
ise
bori
ng
391
Fig
ure
4:
600m
m Ø
per
cuss
ion
dril
l re
amer
for
cen
tre
core
rem
oval
392
Fig
ure
5a:
Sin
gle
lift
(85
ton
s) o
f W
irth
Rai
se b
ore
mac
hine
fro
m s
haft
wit
hin
6 hr
s of
hol
ing
393
Figure 5b: S ing le l i f t (106 tons ) o f 7 .1mø ra i se bo re r eamer f rom sha f t w i th in 12 h r s o f ho l ing .
394
Fig
ure
6:
Bir
ds-e
ye v
iew
of
7.1m
ø ra
ise
bore
d sh
aft
afte
r re
mov
al o
f ra
ise
bore
equ
ipm
ent
•S
pile
s ar
ound
sha
ft•
Ten
denc
y of
B4
Dol
erit
e to
sel
f m
ine
but
arre
sted
by
spil
e(t
op l
eft
of s
haft
)
395
Ad
den
du
m 1
396
Ad
den
du
m 2 39
7
Ad
den
du
m 3
BO
SJE
SS
PR
UIT
- C
HA
RL
CIL
LIE
RS
DO
WN
CA
ST
SH
AF
T
398
