Tag Archives: South Walker Creek

NRW Holdings’ Action Drill & Blast wins South Walker Creek contract

NRW Holdings Limited says its wholly-owned subsidiary, Action Drill & Blast Pty Ltd, has been awarded a five-year drilling contract by Stanmore Resources SMC Limited at its South Walker Creek mine.

The contract, valued at circa A$65 million ($41 million) over the five years, is due to commence in November 2022 and will leverage a workforce of some 35 personnel.

South Walker Creek is an open-pit mine, some 35 km west of Nebo in Queensland’s Bowen Basin. The mine has been operating since 1996 and adopts a multi-bench, open-pit mining method using a dragline, and truck and hydraulic excavators.

With a mine life of 25-plus years, South Walker Creek produced 4.9 Mt of high-quality low volatile PCI coal in the 2021 financial year.

Stanmore Resources acquired BHP’s 80% interest in BMC in May 2022, becoming the operator of South Walker Creek.

FLANDERS AC system retrofit boosts dragline productivity at BHP South Walker Creek

After retrofitting an aged DC 8050 dragline with a safer AC power system, a multi-dragline coal mine operating in Queensland experienced a major boost in productivity and power efficiency, substantially diminished operating costs and a positive return on the investment within 18 months, FLANDERS says.

In 2018, senior management of BHP’s South Walker Creek coal mine was developing a plan for the DRE28 DC 8050, a nearly 40-year-old dragline on which the DC rotating equipment and DC control system had reached the end of their operating service life. The dragline was still operating with the original Westinghouse DC motors and generators, which had also reached their end of service lifespan.

At a minimum, the DRE28 motors and generators needed to be replaced. They could upgrade to new DC equipment that would maintain productivity for another 25-plus years with similar operating costs. However, the DC system required regular maintenance and was at a high risk of extended periods of machine downtime due to waiting for parts and maintenance techs, both of which were harder and harder to find, FLANDERS says.

Another option was to retrofit the DRE28 with an AC system. AC dragline systems were already known to have safety advantages and reduced maintenance costs compared with DC systems, according to FLANDERS. They also had the same service life expectancy of 25-plus years.

The team decided to move forward with an AC retrofit from FLANDERS. In July 2019, the boom was lowered on DRE28 DC 8050 and the on-site retrofit began. After 90 days, the DRE28 AC 8050 was back online.

“AC systems are designed with safety built in,” FLANDERS said. “Hardware compatibility, simpler and safer operating mechanisms and scalability are benchmarks of FLANDERS’ AC system design.”

One of the key features of the AC system is the unique, easy-to-access drive cabinet designed to replace DC motor-generator sets, FLANDERS says. Water-cooled semiconductors remove heat, so the cabinets keep parts protected from debris. This results in a substantial reduction in noise, dust, heat, and rotating parts, and reduced exposure of employees and maintenance technicians to these safety hazards associated with DC systems.

The drive cabinet also eliminates the need for on-site machining to blow out dust, balance parts, clean brushes and other regular maintenance DC systems require.

AC hoist/drag motors

The 690 V AC hoist/drag motors are designed to fit in the same size box as the DC motor, with the same footprint, allowing for easy drop-in installation. No modification to brakes, gearing, or coupling is necessary. Class H insulation and high-output blowers help the motors safely produce a 25% higher kilowattage than the DC motor can achieve.

Arc flash safety system

The FLANDERS AC system design mimicked the DC design in generating low- and medium-voltage interactions. The motors and drive cabinet have a category zero arc flash rating, requiring little intervention with specialists or the need to manually isolate systems within the machine.

There are several systems in place to ensure safety from arc flashes:

  • Metal doors safely hide high-power components, and all doors use Fortress Interlocks to ensure appropriate isolation of high-voltage before access is gained;
  • Electronic control boards can be separated into low voltage panels, nullifying the need to access high-powered areas;
  • Arc flash optical relays installed in each drive cabinet monitor for arcs and trip high-voltage VCBs to reduce potential energy below arc venting requirements; and
  • Fast-acting fuses are located on a) the secondary drive transformer and, b) bridge cabinets feeding to drive line-ups, and the DC bus in drive line-ups.

Ground fault detection

The built-in Bender IRDH265 Ground Fault Monitor eliminates the risk of electric shock, providing a system shut down override at the sign of a catastrophic event. Each drive line-up has a manual ground fault test function to supplement the auto test function of the Bender. This allows electricians to manually verify functionality of the ground fault monitoring system, FLANDERS explained.

The system is programmable logic controlled, which prevents the circuit from operating while the drive is in operation.

Opportunities for optimisation

Where the DC commutator is limited in output, AC capability is expanding and growing for draglines. There is still potential to be unlocked by analysing machine data and implementing optimising upgrades, according to FLANDERS.

AC conversion delivers results

From September 2019 through June 2021, the DRE28 AC 8050 operated at the previous DC 8050 electrical, mechanical and structural settings. In July 2021, after system optimisation, the AC 8050 surpassed the limits of DC 8050 machines, reaching output levels closer to the 8200 DC draglines models, and continued to bank gains in reduced maintenance costs, increased productivity and improved energy efficiency.

A side-by-side comparison of DC and AC dragline operations over 12 months and including three months of data reported after the July 2021 upgrades, shows the results.

The DRE28 AC 8050 is – operationally and electrically – the safest dragline in its fleet, according to FLANDERS, with the drive cabinets and motors maintaining a category zero arc flash rating since installation.

“The overwhelming response from our client was related to the safe and easy operation of the AC system,” Owen Uebel, Strategic Business Development Manager for FLANDERS, said. “Operators were vocal with management about the improved work conditions.”

In terms of productivity, the low-maintenance design of DRE28 AC system has resulted in reduced machine downtime and proportional gains in machine availability. A twelve-month comparison study confirmed that, compared with the DC 8050, the AC 8050 moved an additional 2 million bank cu.m (BCM).

With the July 2021 optimisation, the AC dragline is expected to reach a minimum of 15 million BCM annually in 2022, setting a record for this mine.

An independent study confirmed an 11% boost in power efficiency over the DC 8050 dragline over an operating period of January 1 to December 31, 2020, meanwhile.

“As previously mentioned, one of the major benefits of the AC system is its scalability,” FLANDERS said. “The 2021 optimisation increased the system’s peak power, resulting in a 4.5 second reduction in cycle time with no additional structural or mechanical stress on the machine. This finding was verified independently by MineWare reports and outside consultants.”

The AC system’s solid-state components have substantially reduced the amount of mechanical wear on dragline parts, extending savings across the lifecycle of the machine, according to FLANDERS. Maintenance costs are down over 55% on average (and potentially upwards of 65% based on available data since July 2021 upgrades).

Additionally, the AC dragline’s efficiency translates to 4.5 kilotons of CO2 offset, with major implications. To put that into perspective, at a global price of $200 per ton, that’s $450,000 annually and $900,000 over the two years of this study.

The AC retrofit achieved a return on investment within 18 months of being online, making it the lowest-cost pre-strip solution on the market, according to FLANDERS.

As of October 2021, the mine’s overall electrical and mechanical maintenance expenditures bottom line decreased by 60%.

BHP to sell stakes in Poitrel and South Walker Creek met coal mines to Stanmore

BHP has signed a Share Sale and Purchase Agreement to divest its 80% interest in BHP Mitsui Coal (BMC), an operated metallurgical coal joint venture in Queensland, Australia, to Stanmore SMC Holdings Pty Ltd.

Stanmore SMC, a wholly owned subsidiary of Stanmore Resources Limited, has agreed to acquire 100% of the shares in Dampier Coal (Queensland) Pty Ltd from BHP Minerals Pty Ltd, the subsidiary which holds BHP’s interest in BMC, for cash consideration of up to $1.35 billion. The purchase price comprises $1.1 billion cash on completion, $100 million in cash six months after completion and the potential for up to $150 million in a price-linked earnout payable in the 2024 calendar year.

The sale is subject to the satisfaction of certain conditions, including customary competition and regulatory approvals. This includes approval from the Foreign Investment Review Board. Completion is expected to occur in the middle of the 2022 calendar year.

The BMC portfolio includes significant infrastructure including an 8.4 Mt/y coal handling and processing plant (CHPP) at South Walker Creek (pictured), the 9 Mt/y Red Mountain CHPP (fully owned by BMC) in close proximity to the Poitrel operations, two rail loops and train loading facilities, two Marion 8050 draglines, and a fleet of excavators, dozers and haul trucks, Stanmore said.

BHP Group Limited operates BMC as part of an 80:20 joint venture with Mitsui.

BHP intends to continue operating BMC until completion and work closely with Stanmore Resources to ensure a successful transition of ownership. It will provide certain transitional services to Stanmore Resources for a short period of time after completion.

BHP’s President Minerals Australia, Edgar Basto, said: “This transaction is consistent with BHP’s strategy, delivers value for our company and shareholders and provides certainty for BMC’s workforce and the local community. As the world decarbonises, BHP is sharpening its focus on producing higher quality metallurgical coal sought after by global steelmakers to help increase efficiency and lower emissions.

“South Walker Creek and Poitrel are well-run assets that have been an important part of our portfolio for many years and we are grateful for their contribution to BHP.

“Under this agreement, BMC will transition to Stanmore Resources, an ASX-listed company that has established relationships with Traditional Owners and strong engagement with their workforce and local communities. Stanmore Resources share our focus on safety performance and culture and support Australia’s commitments under the Paris Agreement.”

Stanmore Resources’ existing assets in Queensland’s Bowen Basin include the Isaac Plains Mine and processing facilities, the adjoining Isaac Plains East and Isaac Downs mining areas and the Isaac Plains Underground Project.

BHP, meanwhile, said the review process for its New South Wales Energy Coal is progressing, in line with the two-year timeframe announced in August 2020.

BHP Mitsui Coal and Barada Barna Aboriginal Corp sign South Walker Creek agreement

The Barada Barna Aboriginal Corporation (BBAC), on behalf of the Barada Barna people, have entered into a Native Title Project Agreement with BHP Mitsui Coal Pty Ltd (BMC) for the South Walker Creek Mine in central Queensland, Australia.

It is the first agreement of its kind between Barada Barna Aboriginal Corporation and BMC, and is structured to deliver immediate and intergenerational benefits to the Barada Barna people, according to BHP.

The agreement will, BHP says, provide mutual benefits and certainty for BMC and Barada Barna.

Financial benefits will be directed towards priority community projects that enable Barada Barna people to live and work on-country, strengthening their important connection. The agreement also delivers ongoing financial security for socio-economic purposes and non-financial contributions in the form of contracting, business, employment, education and training opportunities for Barada Barna people.

The agreement will also support for the ongoing development and operation of South Walker Creek Mine – including a framework for the parties to work together on cultural heritage management and protecting areas of cultural and environmental significance.

Barada Barna Aboriginal Corp Chairperson, Luarna Walsh, said the agreement will ensure lasting and sustainable benefits for the Barada Barna people.

“The agreement will not only provide long-term benefits for the Barada Barna community, it will also achieve projects that BBAC have had in the pipeline for a considerable amount of time.

“Importantly, it sets Barada Barna on a path of self-determination. It will ensure BBAC is sustainable into the future and help our next generation of descendants achieve their goals through schooling and university, and employment and training. This agreement also provides BBAC with the ability to diversify our income streams, by creating Traditional Owner business’ that can tender for a variety of contracts on country.

“I’m very proud to have been involved in this negotiation alongside fellow Barada Barna Directors, and, after tough and sometimes testing negotiations, to say we have reached a successful outcome.”

BMC Asset President, Elsabe Muller, said the agreement sets out the long-term partnership with the Barada Barna people.

“We’re looking forward to continue working with the Barada Barna people and contributing to their communities benefitting from sustainable economic, social and cultural initiatives,” Muller said.

“The agreement outlines a path forward for a long-term relationship based on trust, respect and mutual benefit. It will also see BMC and Barada Barna work together in relation to the management of cultural heritage at South Walker Creek and deepen our workforces’ knowledge and understanding of Barada Barna history and connection to country through cultural awareness training.”

The Barada Barna people are the native title holders (determined in September 2016) over approximately 3,000 sq.km of land in central Queensland, where BMC’s South Walker Creek open-pit mine is located.