That Sinking Feeling: International Mining September 2018
That Sinking Feeling: International Mining September 2018
That Sinking Feeling: International Mining September 2018
M
That sinking
feeling
lying orebodies and increasingly challenging “The shaft sinking fraternity can pride itself they do not lead to the advance in development
underground conditions have slowed down on the changed environments in which we rates the industry requires to ensure capex-
shaft sinking rates, adding to the list of issues undertake one of the most challenging aspects intensive underground projects can be greenlit
developers face when trying to finance new of the mining industry today,” he told IM. and, then, turn a profit.
underground mines. These safety improvements are laudable, yet This issue is only heightened by the fact more
Mining engineers and shaft sinkers, alike,
recollect when they could sink 100 m/mth and
get to the bottom of ventilation or services
shafts that much quicker, but, today, average
rates are more like 40-50 m/mth, with anything
above a bonus.
While productivity may have been that much
more impressive four decades ago, safety was
not.
Murray Macnab, Managing Director of Mets
International, puts it into perspective.
“The way they sunk shafts in the past was
productivity and production at all costs and it
took many, many lives; effectively one life for
every 100 m of shaft sinking,” he told IM.
“Today, we sink 1,500-2,000 m shafts without
a single loss time injury.”
Take Glencore's Nickel Rim South project in
Ontario, Canada. The sinking of two concrete
lined shafts simultaneously by Cementation – a
6.1 m diameter ventilation shaft to a depth of
1,680 m and a 7.6 m diameter main access shaft
Redpath and Hasu Megawatt, through their joint venture company, Dayan Contract Mining, reached
to 1,733.5 m depth – occurred without a lost- the bottom of the Number 2 shaft at the Oyu Tolgoi underground mine earlier this year. Photo: Oyu
time accident. Tolgoi underground project
IM
open-pit mines will have to transition underground in future years to
OUR
continue operations, and a greater number of recent discoveries are
coming under barren cover that, should they become deposits, will require
vertical development.
One would assume shaft sinking rates are going to have to speed up in
order for future mines to come on stream.
Acceleration
COMPETENCE,
YOUR
Those manufacturing shaft sinking equipment and the contractors carrying
out this specialised work are doing something about this.
Cementation Canada, after successful use at Shaft 10 at the Resolution
copper project in Utah, US, is looking to include shotcrete as a temporary
support measure in its own shaft sinking cycle.
The challenging conditions (temperature, water ingress, etc)
experienced sinking the 2,116.2 m deep shaft saw the company remotely
INNOVATION.
apply fibre reinforced shotcrete as a temporary support measure.
“With shotcrete, we remove people from the face. Instead of a miner
with a handheld drill carrying out support work in the shaft wall, now we
bauma CHINA, Shanghai, SNIEC,
have a remote operator shotcreting,” Roy Slack, President of Cementation November 27–30, 2018
Canada, told IM.
This brings obvious safety benefits, while speeding up the whole
development process.
And, the company has also gone beyond what was traditionally thought
of as the ‘limit’ for raiseboring within shaft sinking.
It used a large diameter raisebore to help sink a more than 5 m diameter
shaft down to 1,500 m at Alamos Gold’s Young-Davidson mine in northern
Ontario, Canada.
Redpath, meanwhile, is looking to redesign its conventional shaft
sinking system to allow “safe concurrent tasks of the cycle to be carried
out,” according to Melong.
“This requires innovative approaches to mucking and lining of the
shafts, currently underway within our group,” he added.
These and other developments have Macnab thinking contractors and
engineers can get a 10-20% improvement on the current monthly
development rates with conventional drill and blast technology.
“I don’t believe 40-50 m/mth is going to be where it is forever,” he said.
One company that has exceeded such rates is Aveng Mining, which is
currently working on sinking Shaft 1 at the Platreef underground project on
the northern limb of South Africa’s Bushveld Complex.
This project, majority owned by Ivanhoe Mines, requires the sinking of
two shafts for ventilation and hoisting with the first 7.25 m diameter shaft
going down to 980 m depth. The second shaft, which will have a rock
hoisting capacity of 6.4 Mt/y, will be a 10 m diameter, 1,104 m deep
concrete-lined shaft.
Aveng, through its Aveng Shafts & Underground subsidiary, started
sinking Shaft 1 in July 2016 and, on April 23, 2018, reached a depth of more
than 750 m below surface, allowing construction of the first mine
development access station.
In the 12 months to June, development metres at Shaft 1 averaged
around 50 m/mth, Aveng Mining Senior Contracts Manager Patric REGISTER NOW!
Scheepers told Mining Review Africa recently. March saw the company
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achieve 54 m/mth, which Scheepers said was a record.
These rates were achieved by moving to a continuous operations model
with 340 permanent employees and an additional 50 subcontractors,
Scheepers told the publication.
The company also transitioned from a conventional sinking approach to
a two kibble-loading methodology which removed employees from the
shaft bottom during mucking operations.
“This required careful engineering and change management at the time
International Trade Fair for Construction Machinery, Building
and was a major success,” Scheepers said.
Material Machines, Mining Machines and Construction Vehicles.
But, even so, Aveng would not even be carrying out such work if the
www.bauma-china.com
SHAFT SINKING
hile the debate about mechanised shaft sinking goes on, Partners, Clough Projects International and RUC Cementation Mining) set
W conventional drill and blast projects continue worldwide. to design, construct and commission the sinking and lining of Shaft #3 and
In July, Barrick Gold confirmed contractor Thyssen Mining had mobilised #4.
to its Turquoise Ridge site in Nevada, US, to carry out work on the sinking This involves blind sinking and concrete lining of the two 10-11 m
of a third shaft at the operation. The development, with additional diameter shafts down to depths of some 1,150 m for ventilation.
processing capacity, is expected to roughly double annual production to Lastly in contracting, earlier this month Jastrzębska Spółka Węglowa,
more than 500,000 oz/y. one of Europe’s largest coking coal miners, signed an agreement to
The project consists of sinking and equipping a 24-ft (7.3-m) diameter, purchase a 95% stake in shaft sinking specialist Przedsiębiorstwo Budowy
concrete-lined shaft to 3,250 ft (991 m) depth, according to a technical Szybów (PBS) from the Kopex Group.
report filed earlier this year. Shaft sinking will include two skipping levels, The PLN 205.3 million ($55.6 million) agreement came as a result of
a water pressure break level, and a shaft bottom pump level, while FAMUR SA’s acquisition of Kopex, completed earlier this year. PBS has
equipping includes a headframe and collar house; hoists and hoistroom; carried out more than 132,300 m of shaft sinking, including 35,000 m in
shaft steel; surface and underground material handling; and a shaft hard coal mines and 67,000 m in ore mines.
bottom pumping system.
Cementation Canada, in partnership with Murray & Roberts, is busy
sinking twin shafts, each 7 m in diameter, down to 1,080 m depth at the De
Beers’ majority-owned Venetia diamond mine in South Africa.
In North America, Cementation Canada is also carrying out work on
Glencore’s Onaping Depth nickel-copper project in the Sudbury Basin of
Canada. According to a March 2 report in Northern Ontario Business, the
project includes the construction of a winze from the 1,200 m level laterally
off the workings of Craig mine to access some 14 Mt of ore, 2,500 m from
surface. The first 700 m of the winze will be raisebored down to the 1,900 m
level and then slashed and extended beyond that to the 2,650 m level
using conventional shaft sinking technology.
Redpath’s Melong said the company was winding down operations at
two Canada potash shaft sinking contracts with “composite liners,
underground freeze conditions and the rehabilitation and upgrade/
reconfiguration of an existing shaft hoisting system”, while, in Europe, the
company is completing two other conventional frozen shaft sinking projects.
Cementation Canada’s recent shaft sinking work has focused on
In Mongolia, the GCR Mongolia joint venture won more work at Oyu
removing people from the shaft bottom, while using innovative methods
Tolgoi earlier this month, with the three partners (Gobi Infrastructure to speed up sinking rates
re haulage and ventilation usually requires the sinking of large A Drillcon is another contractor that has shown big interest in our Epiroc
Q How does the Easer fit into Epiroc’s wider raiseboring offering? Is there
need for further mobile raiseboring models to meet customer demands?
A The Epiroc Easer rig has been a really good complement to both our
Epiroc raiseboring products and production drilling equipment (replacing
slot raising with ITH). We have seen a demand for a lower profile model
that better fits the smaller drift sizes in the medium size segment (4 x 4 m
– 4.5 x 4.5 m).
Q Apart from Pybar, what other companies have shown an interest in using
Lundin Gold recently purchased an Epiroc Easer rig for its Fruta del Norte
the Easer? operation in Ecuador
IM
what it benchmarked with conventional drill and blast.
The only other confirmed SBR order from the mining sector is for Sirius
Minerals’ potash project in the northeast of England (see more details in the
DMC Mining Q&A).
The company is attempting to build a 10 Mt/y polyhalite mine that makes
use of a mineral transport system, located in a 37-km long and 4.3 m wide
tunnel at an average depth of 250 m below ground.
No silver bullet
Given the inherent variability of underground deposits, mechanical cutting
is unlikely to be suitable for all underground developments.
SHAFT SINKING
MC Mining Services (KGHM Group) is one of the rare contractors to materials up and down between the surface and work face. We have gone