HIGH PROFILE
was a deviation from the initial timeline, the new
approach meant the changes could be applied
with minimal disruption. The revised shaft depth
to 914 m was commissioned and hoisting of
production ore was within three years of the start
of construction.
Cementation has a full Project Delivery System
(PDS) to give a roadmap for successful project
outcomes. Additionally, there is an Engineering
Project Delivery System (EPDS) that is aligned
with the overall PDS, but is specific to engineering
processes and procedures. As can be seen,
continuous improvement is a function of
Cementation’s Internal Responsibility System for
all areas of work including engineering, site
construction, quality, environmental and, of
course, health and safety. When everyone works
safely, this is reflected in the project success and
the schedule and budgets.
With the shaft specific phases completed,
Cementation has augmented its crew with civils
contracting personnel given the highly specialised
nature of some of the civils work being
undertaken as part of the ore and waste handling
systems to ensure early gains are not lost and the
client’s production profile is maintained.
Using rope guides, the hoisting rate of 8,000 t/d
was achieved with 18 t skips travelling at 15 m/s
from the mid-shaft loading pocket (914 m depth)
and 10,000 t/d with skips travelling at 21 m/s
from the shaft bottom location (1,500 m). This has
surpassed the original design production rate.
IM: What safety procedures has Cementation set
up to enable work to continue even with social
distancing measures in place?
Cementation: Our projects have had various
responses to the social distancing requirements,
which has led to a change for some in the rotation
schedule to reflect the currently understood
incubation/asymptomatic carrier transmission
schedule. For the current work at Young-Davidson,
Cementation has brought in additional personnel
carriers to enable distancing while travelling.
Employees wear masks when travelling in vehicles
as proper social distancing is challenging.
Each worker at Young-Davidson for
Cementation is issued with two masks every shift
so they have options if social distancing is not
possible. We have also instituted staggered start
times and reduced the capacity of the cage for
travelling, with a mask requirement for all
personnel within the cage, to help with social
distancing measures.
IM: How is the project seen as representative of
the company’s wider shaft sinking expertise?
Cementation: For Cementation we have always
enjoyed being involved at the early stages of
projects to promote change and have the most
opportunities to make optimisation suggestions
A long section of the shaft sinking layout at
Young-Davidson.
that could be carried forwards. With our heritage
in traditional shaft sinking and technically
challenging projects, it should be noted that we
are open to any and all innovations that do not
compromise safety on our projects.
Throughout our group we have been born from
innovation in shaft sinking from our inception with
the development and patenting of the
‘Cementation Process’ for sinking through difficult
water bearing ground, which today the industry
knows as cementitious grouting. It has been a
natural evolution to add a wider variety of sinking
options such as large diameter raiseboring,
successfully, in hard-rock conditions. Our strong
in-house engineering and engineering studies
groups, supported by our contracting groups for
constructability and safety, allow us to consider
options for changing conditions and scenarios.
This flexibility is further augmented by our
approach to commercial and contractual
arrangements. Oftentimes, this allows our
approach to pivot with client requests, rather than
be locked into rigid arrangements that cannot
easily accommodate change. Cementation
introduced target style alliance contracting into
the North America mine contracting market, with
the first active sinking project to utilise this
approach being Falconbridge’s (now Glencore)
Kidd Mine D #4 Shaft project. Another technically
challenging project, a winze in an operating mine,
which we proposed be worked on two separate
sections to fast track the schedule, was then
connected for the final design. The parallels to the
legs approach at Young-Davidson and the similar
benefits realised are apparent.
IM: What aspects of this project will help the
industry move forwards in terms of speeding up
development rates, improving safety, lowering
shaft sinking costs, lowering mining’s
environmental footprint, etc?
Cementation: Cementation takes care to consider
all stakeholders and relationships; the project
culture and morale can be as important as the
technical expertise or contracting ability, all things
being equal.
As is the case at Young-Davidson, close
integration between the owner and the contractor
teams over the entire evolution of the scheme,
with flexible engineering and planning being
paramount, are key for successful collaboration
and project success. Effective contractual and
commercial formats that foster this attitude are
vital to give the technical personnel the ability to
adapt to changing conditions – in the ground or
the markets – and deliver a successful project
based upon criteria that may be fluid over time.
Noting that shaft sinking is itself a
specialisation, there are many subsets to that
discipline and new options and approaches
regularly arise, often organically as an enhancement
or combination of existing techniques.
Certainly the use of large diameter raiseboring
elaborates upon earlier smaller borehole hoisting
shafts, but, with advances in drilling technology
and accuracy, the options for the application
become wider. It should be noted there are four
key points that should be addressed for
successful large diameter raiseboring, especially
for their incorporation into shaft projects such as
this in an operating mine:
n Is the size and length within current
capabilities? Legs less than 1,000 m long and
diameters less than 6.1 m;
n Is the ground suitable? Sidewall stability and
stand up times until ground support installed
are a must. Are water inflows an issue for
flows or destabilisation?;
n Do you have access to the bottom of the pilot
(for survey) and ream (for waste handling)?
Necessary for installation of reamer head on
drill down, ream up approach; and
n Can you handle the waste underground? A
5.52 m ream may progress at 0.5 m/h,
generating 12 cu.m of in-situ volume (or 40
t/h) of spoils that may have to be blended
with other waste for system compatibility.
Specifically at Young-Davidson, the
opportunity of the MCM shaft for hoisting
raisebore cuttings was an enabler for the
project to take advantage of the large
diameter raisebored shaft approach for a
borehole hoisting shaft. IM
SEPTEMBER 2020 | International Mining 79