MINExpo Issue - MINING.com Magazine

Environment & Communities
By Ralph Gunness, Environment
Manager, Arrow Energy
As one of Australia’s leading coal
seam gas producers, Arrow
Energy recognizes that corporate
success is much more than building
a bottom line. The company’s greatest
responsibility is operating in a sustainable
and intelligent way that leverages
our financial, technical and intellectual
resources to the benefit of our investors,
employees and communities.
In Australia, Arrow has four producing
projects, which account for more than
20 percent of the state of Queensland’s
overall gas production. Three of these
projects are located near Dalby in the
Surat Basin, west of Brisbane.
Dalby is currently experiencing one
of its worst droughts in history. The local
aquifers are depleting and have not been
significantly recharged in over a decade.
The local community is struggling to
obtain long term sources of water.
Arrow draws quantities of water from
coal seams deep underground as part of
the gas production process. Traditionally,
this water is stored in large evaporation
ponds near the wellhead as it is brackish
to saline in quality and, as such, must be
contained.
Arrow is committed to recycling this
water for the benefit of the wider Dalby
community.
Surat Basin Coal Seam Gas
Characteristics
The quantity of water within coal seams
varies due to a number of factors, including
depth, location and well completion
techniques. Arrow estimates that its Surat
Basin operations could produce up to 15
megalitres (ML) per day.
Analysis of the Coal Seam Gas
(CSG) water completed exclusively for
Arrow’s Surat Basin gas fields resulted
in no detectable levels of hydrocarbons,
carcinogens, radioactivity, mercury,
copper, silver, arsenic, tellurium, nickel,
boron, lead and selenium, and halogenated
methanes.
54 MINING.com September 2008
Investing in Australia’s
Sustainable Future
Current Arrow coal seam gas water
recycling projects include:
1. the dalby Council Potable Water
Supply (reverse osmosis plant
upgrade)
Arrow ‘s coal seam gas water in the
Surat Basin has been filtered in carbon
for generations and is about one-sixth
the concentration of sea water. Further,
it does not contain the elements that are
found in waste water, which makes it ideal
for reverse osmosis treatment. In most
cases, reverse osmosis is an expensive
process and not practical for areas where
potable water is in abundance. However,
the viability of a reverse osmosis plant increases
in drought-affected areas where
declining water supplies increase the
value of water. While this value is hard to
determine, one thing is for sure - the cost
of not having any water at all far exceeds
its costs of production.
Dalby Council, in conjunction with
Arrow, has initiated the development
of a new reverse osmosis plant to treat
coal seam gas water from our nearby gas
fields. The company plans to supply up
to 5ML per day to the plant for household
and industrial use over a 15 year
period.
The AU $16 million plus plant is
scheduled for construction in the first half
of 2008 and is being jointly funded by the
State and Commonwealth Governments,
Dalby Town Council and Arrow Energy.
Arrow Energy will supply water produced
from its Tipton West coal seam gas operation
to the plant at no cost, but will benefit
from certain avoided water disposal
costs in the field.
2. irrigation
The development of two additional reverse
osmosis plants is currently being considered
in the Dalby region to allow irrigation
use of Arrow’s coal seam gas water.
Arrow conducted a regional economic
analysis study of a potential irrigation area
using recycled coal seam gas water. This
study concluded that treated water would
increase the region’s agricultural output.
This project is ongoing.
3. Salt Water fish farm
Arrow Energy, in conjunction with the
Queensland Government’s Department
of Primary Industries and Fisheries (DPI),
is currently conducting a research project
to investigate the viability of farming salt
water fish in its coal seam gas evaporation
ponds. 15,000 fingerlings have been successfully
raised over the past 18 months
by the DPI in coal seam gas water. The
fingerlings comprise Mulloway species.
The trial is continuing but represents a
promising opportunity to utilise the water
for large scale aquaculture.
4. Beef feedlots
The Guidelines to the Australian Water
Standards specifiy that raw water to be
used for stock water should not contain
salt greater than 8,000 ppm salt for nonpregnant
beef livestock and 6,000 ppm
for pregnant beef livestock. Untreated
coal seam gas water is currently being
supplied to two local feedlots, replacing
upper aquifer bore water at the rate of up
to 4ML per day.
5. Municipal Waste Water treatment
Arrow is investigating the use of coal
seam gas water as a replacement for
potable water used in municipal sewage
treatment systems.
6. Supplying Wash Water to local
Coal Washing Plants
Coal seam gas water drawn from Arrow’s
Surat Basin fields is used by coal mining
companies to wash coal, thereby allowing
the upper aquifer to recharge.
In a regime of diminished water
supply, this kind of water has the potential
to be of tremendous value as a sustainable
resource for rural projects and town
water consumption. Although further research
and consideration of agricultural,
environmental and economic macro factors
is required to determine this value,
Arrow is committed to finishing what it
has started and continuing its investment
in Australia’s sustainable future.