Andrew Cole
Good morning to everybody joining us on the call this morning at our OZ Minerals third quarter report. I'm pleased to have here today Luke Anderson, our Chief Financial Officer; also, Bob Fulker, our Chief Operating Officer; and Claire Parkinson, our Head of Corporate Affairs.
So I'm going to take you through a short presentation, which we have [indiscernible] this morning, and then we'll open the call up for questions. To start out though, I think this has been quite a solid quarter given some pretty challenging events, and we will touch on some of those through the course of the presentation.
Weather through this last quarter has been quite challenging for us and, of course, you're all aware that we had a couple of weeks power disruption through the very end of last quarter but most substantially in this quarter. So we will touch on those as we [indiscernible].
Luke will mostly touch on the weather through the last quarter as it impacts our cash balance and our receivables. I will touch mostly on the power disruptions as this impact the physical operations.
Our focus on capital discipline has certainly continued through the quarter and our cost base continued to reduce, which was really good to see. Significantly, we saw our copper production up by about 5% from last quarter, and we're now on guidance for copper for the eighth consecutive quarter, which is very much in line with our strategy which I have talked with you all about before.
As I mentioned, unfortunately, largely as a result of recent 2-week power outage, we have had to reduce our annual gold guidance, which I will come back and talk to you about soon. But notwithstanding this, all other guidance remains on track for the year.
Our growth platform continues to progress and I will elaborate more on this in due course. And of course, I will answer questions at the end if you have them.
There are 2 pages of disclaimers in the deck here, please take note of both, and especially the forward-looking statements as we will be making statements about this quarter, Q4, throughout the presentation. So before I get into some of the detailed results, I just like to touch back on the company strategy and some of the internal work that we are doing in the business to keep simplifying our systems and our processes and also to build a strong and innovative culture in the group.
So over the last 3 months, there's a few new things that we've launched internally. A refreshed strategy, which includes quite a bit more detail around what and how we are working to try and align our people more and more towards the strategy that we've got in place.
We've launched a new intranet, which has been a combination of a lot of work, of course, but it's very powerful and important because that's the delivery platform for many of the systems that we are using. We also launched a new internal collaboration so-called [indiscernible] to help build connectedness throughout the business and to enable collaboration.
We're certainly also continuing to build the capacity of our senior leadership team and, as I mentioned last quarter, we've now implemented 9 new policies for the company. So that's a total of 9 now and that's a reduction from over 17 that we had in place last year.
So through the next quarter, we are to complete the writing of our internal simplified corporate standards. We will go live with a new ERP system, so our SAP implementation is almost complete and we'll switch that on in less than 2 weeks.
We're in the middle of building our new life of mine plan and our 5-year budget, and we're going to start a more intense program around people development. Let me turn to the Q3 summary.
So in essence, we're up 5% on copper production to just over 28,000 tonnes this last quarter as compared to Q2. We're continuing our focus on capital discipline.
Now I am pleased to say our C1 costs are continuing to come down at just over $0.70 a pound, down again from last quarter. So that's down about 6% now from the start of the year.
We've also continued our procurement savings program, and we're now up to $29 million of annualized savings to date. And we are on track to hit our $40 million savings by year-end.
As you know, we have completed -- we started our buyback program. We've now completed $19 million of that buyback program, and we paid out an interim dividend of $18 million.
At Carrapateena, the box cut is now complete and the Tjati Decline is progressing as scheduled. Scoping studies for the West Musgrave project in our joint venture with Cassini Resources is well underway and I'll touch on that a little bit later.
And we also exited the Jamaica joint venture, which I'll recap a little later on as well. Looking forward, and I am very pleased to say, that our Carrapateena pre-feasibility study is ahead of on schedule and we will release that next month, so in November.
And we also have our Prominent Hill resource and ore reserve update and new mine strategy almost ready to release, and we'll bring that to you in late November as well. As a result of some of the power outages, just as a summary here, we've lost 2 days in quarter 3 due to the power outage and 12 days in quarter 4.
So the bulk of the impact for that -- from that power outage will actually come through in the Q4 results. We did lose some capacity in different pieces of the business but I would like to point out that the site leadership team, especially at Prominent Hill, I think, did a fantastic job through that period.
They managed to keep the open pit operation running at full capacity, and we continue to build run of mine material throughout. The underground, whilst it stopped immediately post the power failure, they have progressively ran the underground operation up through that period utilizing temporary generation, and that allowed us to build an underground stockpile, which we're now starting to use given the plant is back up and running.
Unfortunately, we have had to reduce our gold guidance by down -- down by about 10,000 ounces to 115,000 ounces to 120,000 ounces. So I think I'll draw back on these impacts as I go through the presentation.
We turn to safety. For the quarter, total recordable injury frequency rate is at 6.3.
This unfortunately compares to 4 -- 5.81 in the prior quarter, so we've seen an increase in our TRIFR. The underground operation at Prominent Hill is the prime contributor to this increase, so we see more injuries in our underground part of Oz Minerals than we do in any other part of our business.
So a couple of months ago, we sat down with Byrnecut our principal contractor and worked on an intervention plan to significantly improve the performance from a safety perspective of the underground operation. And Byrnecut have been progressively putting this program in place.
And whilst it's not a trend, I am pleased to say that September had the least injuries in the underground operation as compared to any other month in the year. So the team is working hard on this, and I expect to see the safety performance improved in time.
More broadly and across the other projects, we have started community consultation for the Carrapateena project, and we're working very closely with the Kokatha people to create a partnering agreement. I'll touch on this a little bit later.
The company received a few awards through the month, a couple of note, one of our senior environmental advisers was announced winner of the Exceptional Young Woman in Australian Resources award. I think this is just representative of the types of people that we have in the business.
And the team at Prominent Hill operation won an industry collaboration award at the South Australia Training Awards. And it's great to see these sorts of incentives in the business as it helps people sort of aspire to greatness, if you like.
So what I'm going to do now quickly is hand over to Luke to take us through the cash position, and then I'll get back into the operating analysis.
Luke Anderson
Thanks, Andrew, and good morning to everyone on the call. I'm pleased to announce a very healthy unaudited cash balance of $509 million at the end of September quarter.
However, whilst [indiscernible] continues to generate strong positive cash flow, we incurred a number of short-term impacts to our cash balance. Working capital increased by $81 million for the quarter, predominantly due to increases in both trade receivables and ore inventory.
I would note that around $20 million of the increase in the ore inventory, however, relates to noncash cost of capitalized depreciation. Trade receivables increased significantly to $151 million, which was up $57 million for the quarter, mainly due to wet weather disruptions to our logistics, delaying shipments to later in the quarter and thus, delaying sales receipts.
The chart on the slide demonstrates the impacts of the rain for the quarter, which -- where we lost 16 logistics days, which is much higher than the comparable time in previous years. As guided previously, a one-off amount of $29 million was paid in July for the 2008 class action settlement and defense costs.
$14 million was spent on developing the Carrapateena project, with $9 million spent on pre-feasibility work and part purchases for the autoclaves, which are long lead items, and another $5 million spent on the decline development. As announced previously, all Carrapateena costs were capitalized from the 1st of July.
$19 million was spent on the share buyback during the quarter, bringing the total program spend to $26 million. And a further $18 million payment for the interim dividend of $0.06 per share was also paid.
An additional 19,000 ounces of gold was hedged in the quarter, bringing the total amount of gold in the ore stockpile hedged to around 190,000 ounces at an average price of AUD 1,731 per ounce. Just to recap, this hedging program begins to mature in quarter 3 2018 and runs through to quarter 3 2021, matching the period over which ore stockpiles are expected to be processed and sold.
As flagged in the June quarterly, from 1st of July, we implemented our strategy of locking in the copper price at the time of concentrate shipment through derivative transactions. This strategy has the benefit of narrowing the time between incurring the cost and locking in sales price and providing greater certainty of revenue earlier.
So looking forward, we expect the trade receivable balance to normalize in the fourth quarter, which will consequently increase our cash balance, along with the ongoing strong cash generation from Prominent Hill operation. Just the end of the quarter, we have already received $80 million in sales receipts.
We also expect our ore inventory to continue to build as we continue to accelerate mining of the open pit at a lower strip ratio and benefit from the increasing ore from the underground. So I'll hand back to Andrew.
Andrew Cole
Yes, thanks very much, Luke. It's obviously very nice to see that some of those receivables before the unwound of $80 million fully come back into our account.
Whilst the Q3 has been -- has proven somewhat challenging with rainfall, as Luke said, we've lost some 16 days through the quarter of being able to haul concentrate to our site. September -- I think September was one of the weakest on record for South Australia, so it has been sort of an unusually wet period.
As I move through open pits and underground processing plant, I think it's pleasing to hear the wet weather has not particularly impacted the operations, really [indiscernible] hauling concentrate inventory. With the open pit, the open pit has generally performed quite well.
We do see some time lost early in Q3 when we had some huge rainfall but more due to a basement wedge failure that happened in an end site unit lower down in the pit. It was a small block of ground that we were monitoring for some time, and we shut the ramp whilst that block is closed and [indiscernible] down the ramp, and then we continued operations.
We have also updated our benchmarking data through AMC recently, as we do continuously to understand how we're comparing and performing to our peers. The report gave positive recognition of Prominent Hill's operating cost and productivity measures.
Unit cost, as you will know, really only marginally increased year-on-year, despite the material reduction in material movement and haul distances substantially increasing. The excavator operating hours remain in the first quartile performance, which is very pleasing to see given excavators are the primary determining factor of our unit cost.
There were a couple of opportunities highlighted through the reports. One in blasting costs and the other one is auxiliary equipment costs, which we'll focus on over the coming quarter.
So looking forward, the open pit ran right through the power failure. So the open pit continue to perform well.
We are focused on capital discipline in the pit. We're continuing to focus on the run of mine rehandling and the effective cost control rehandling our large inventories which we are building.
And now out in the second quarter, we are -- we've input our pit dewatering infrastructure in place, and we've successfully tested that for the remainder of the life of mine. And this, of course, will help mitigate any future impacts of high rainfall events.
As I turn to underground, last quarter we mined just over 0.5 million tonnes of ore, and a nice high grade of 2.29%, which is a significant increase from last quarter. Our actual planned grade was a little bit higher than that at about 2.4% as we mined some really high-grade stopes that were in sequence.
That material is still flowing, of course, through our plant this quarter. Our average grade for quarter 4 will be just under 2%.
During the quarter, we also added a new underground truck, a loader and a cable bolting rig. They all came online as part of our ramp-up to the 3.5 million to 4 million tonnes per annum underground mine which we are building.
There are a number of other improvements in infrastructure, in roadways, in some developments in dewatering programs, all being put in place to enhance the productivity of the underground operation. They also completed successfully an explosives and mesh trial, which resulted in some cost savings, which are now being baked into our plan.
The second decline being constructed for some time is on schedule. It's now 550-odd meters on track for 2017 completion.
During the quarter, we also built a short third decline, which is about 75 meters long, which now connects the bottom of the Prominent Hill open pit into the Malu part of the resource. This is acting as a short-term haulage route.
And it will become a long-term ventilation circuit. And we're going to use this to increase as a mechanism to help ramp us up to 3.5 million to 4 million tonnes per annum.
And we will chip short from underground into the open pit that will allow large open pit trucks to move that material. If I move on to the processing plant.
The processing plant performed well in the quarter, 2.4 million tonnes of ore mill, which is 6% higher than the last quarter. Plant recoveries continue to be high, about 86% for copper and 72% for gold.
The third and final processing plant shutdown was also undertaken in the quarter, which means we do not have a plant shutdown in Q4. The repaired SAG mill girth gear has continued to perform very well, and the replacement SAG mill girth has now been manufactured and is en route to site.
With regards to power, as I mentioned before, we lost 3 days in Q3, 12 in Q4. This means we've effectively already lost 14% of the available time in this quarter with the plant.
So as a result, we have reached sequenced out on the mine material through the plant. We will unfortunately see lower gold, but we will be able to hold our copper guidance as stated.
We're also trialing a new pre-crush stage for harder ores to help plant throughput. This is a trial that will run through part of this quarter.
During the power outage, we were able to complete a number of unplanned maintenance activities. And it was very pleasing to see that through that whole period, there were no injuries, which is, of course, can be a higher risk set of activities when working on plant.
The plant started up exceptionally well and exceptionally quickly, and that was due to the people ramping and cleaning up of plant of the crush stock last month. And just a reminder, with all of the noise around electricity, the Prominent Hill electricity prices are fixed until mid-2017.
So Luke, can you take us through the cost flows?
Luke Anderson
Sure. So despite the latest operational challenges, I'm actually happy to say we've maintained full year guidance across all our cost metrics.
Our C1 costs of $0.71 per pound reflects the consistently strong performance in the third quarter, with the year-to-date result of $0.73 per pound at the lower end of our annual guidance range of $0.70 to $0.80 per pound. C1 costs, which continued to be in the bottom quartile, benefited from more payable copper produced.
Mining costs were low, particularly in the open pit, with less activity due to wet weather and the geotechnical basement event. There was a larger open pit mining deferral with a short-term increase in stripping ratio predominantly driven by lower ore mined.
However, as the result of the less ore mined, the ore inventory increase is smaller than quarter 2 as reflected in the waterfall chart. We've achieved a year-to-date all-in sustaining cost of $1.18 per pound, which keeps us well in the lower end of the cost curve.
Open pit mining unit cash costs in quarter 3 of $6.30 per tonne mined were lower than the prior quarter and reflects the embedded improvements in efficiency achieved. The stripping ratio was higher at 1:1 compared to 0.8:1 in quarter 2, and we continue to mine ore at a lower cash cost of around $12 per tonne.
Underground operating costs of $53 per tonne mined were higher than quarter 2 primarily due to lower ore tonnes and higher operating activity and development. Our cost savings initiative has now locked in $29 million in annualized savings, with the current target of $40 million in annualized savings to be realized by the end of the year when we expect to complete the formalized procurement cost savings program and move into an embedded lean operating environment.
In summary, we have had another strong cost quarter and showing resilience in continuing to deliver to guidance, which puts us in a solid position in the lead up to the final quarter and the full year results. I'll hand back to Andrew.
Andrew Cole
Thanks, Luke. So let me turn now to Carrapateena, our new growth project.
In summary, the project study and decline are all on schedule. So during the quarter, we had PYBAR, our selected underground development contractor, mobilizing the site.
The box cut at the Carrapateena site is complete as you can see in the photograph on the screen. We have a successful first firing for the decline on the 29th of September, and underground development as of today is about 70 meters down the decline.
So they have only just got out of the weather profile, so they're taken it pretty slow to keep a nice, clean decline profile on the way through. And we expect to see the rate of development pick up now that they're into [indiscernible].
Surface infrastructure is mostly in place. We've got camps, offices made into yards, magazine and lay down areas in place.
The PFS engineering of the mine, the processing plant and the supporting infrastructure is almost complete, and market pricing is mostly complete, with the full project cost revision underway currently. So I'm pleased to say that the study is quite a way ahead of schedule, and we expect to release the Carrapateena PFS next month in November.
From a stakeholder perspective, as I mentioned earlier, we've been actively working with traditional owners of the land, the Kokatha people, on our partnering agreement. That is going very well.
And we expect to be able to sign our initial partnering agreement in the next couple of weeks. Community consultation has also commenced with state and local governments.
It started with the communities in Woomera, Port Augusta, Whyalla and Roxby Downs area. And we started the process with the indigenous groups, Kokatha Uwankara in the far west aboriginal cooperation.
Those said, community consultation sessions have been incredibly well attended. This is a really a good feedback and some constructive input into how we should think about the design of the operation.
Turning to the PPP. The feasibility level engineering of the concentrate treatment plant has continued.
The titanium plate for the autoclave has been ordered and autoclaves purchase orders have now been established. These are the 2 longest lead items included in the spend that Luke has really talked about at Carrapateena.
Drill [indiscernible] from the most recent round of drilling at Carrapateena had been taken through hydromet pilot plant starting early next month. So we should be able to bring you some results from this [indiscernible] we're testing later this year.
As discussed last quarter, we are focused on building a hub and spoke type model here in South Australia. There are enormous benefits, we think, to be realized in the gold pattern with this type of model.
A centralized CTP facility can then be used to treat concentrate from Carrapateena, Prominent Hill and any other location that we choose. We have several locations that we are progressing for a concentrate treatment plant location, and we're still in negotiations with the coordinator on our Whyalla options.
So I'm not going to say too much more about Carrapateena as we are releasing the PFS and all the details that go with that shortly. Let me talk in turns of growth.
So on exploration and growth. On this slide, you can see our growth pipeline.
It's very pleasing to say that there are now many more options and opportunities sitting in our pipeline than there certainly was a year ago. So over last year, we've managed to sign 5 additional joint ventures on various opportunities throughout Australia.
During the quarter, we signed a new agreement with Mithril Resources to explore 7 new exploration licenses in the southwest of South Australia. This area is being called the Coompana district.
It's quite a virgin country when it comes to exploration. It's one of the oldest belted rocks in Australia, which had seen almost no exploration.
It's very highly prospective for magmatic copper and nickel. And the reason we've taken out this joint venture and these exploration licenses is because the South Australian government has committed funding to collect new high resolution geophysical, geochemical and drilling data in this region.
So we expect to see some new targets pop up through the startup. As I mentioned earlier, we have withdrawn all of our activities and funding from our Jamaica joint venture.
In recent times, we have seen some quite encouraging results coming from Jamaica. But after a careful review a little earlier this year, we decided the probability of a commercial operation coming from any of that data was low.
So we've taken the decision to exit Jamaica. I think in line with our capital discipline and our very focused exploration strategy, it's very important that we exit projects just as quickly as we do find new projects.
So I'm quite positive and optimistic that the exploration team came to the conclusion that we should exit. We are continuing to complete due diligence on external opportunities, and I can confirm that we are still on track to spend the guided $10 million to $15 million in exploration this year.
On West Musgrave, so this is one of our newer joint ventures that we have signed with Cassini out of Perth. We signed this joint venture to earn up to 70% of the West Musgrave Project.
And that project consists of 2 resources and a whole route of expiration targets, meaning with very good intersections in them. We have now officially signed the joint venture agreement and we've agreed our scopes of work, and we've commenced spending the committed $3 million for the next 12 months.
The focus of this work is going to be on metallurgy and the operation scale, which will also look at infrastructure such as transport, power and water costs. We expect an initial drill program to start in November.
So we'll bring you updates on this project as they occur. Our joint venture with Minotaur around Prominent Hill called Mount Woods is progressing.
It has been somewhat difficult over the last few months due to the amount of rain we've had up at Prominent Hill. But rain in Central and South Australia doesn't make it very easy to get drill rigs moving around, so there's been many interruptions.
But we have drilled a couple of the holes on one target. That target turned out to be a schist with pyrite and pyrrhotite.
So not of interest to us, we've moved on to the next target. We have completed additional ground geophysical surveys, and we will continue working our way through drilling these few extra targets, all within about 30 kilometers of Prominent Hill.
And lastly, but certainly not leastly, our exploration program. Our partnership with Minotaur in Queensland on Eloise has been actually quite encouraging.
So we have drilled a couple of strong EM conductors just north of the Eloise deposit. These targets lie relatively shallowly at 100 meters, 200 meters, respectively.
The first target that we drilled, we intersected narrow quartz pyrrhotite chalcopyrite brecciaâs and some quite wide zones of stringer hosted mineralization, hosted chalcopyrite. The breccia texture of the mineralization looked very similar to those you see on the peripheries of the Eloise copper-gold just to the south.
So we're quite encouraged by this. We have just approved internally a third work program of another 1.5 kilometers of drilling and some infield electromagnetic geophysical work, which the teams are planning to undertake over the next month or so.
This, of course, still sits inside the $10 million to $15 million of guided exploration cost. So we're certainly looking forward to seeing the results of these.
So let me just recap. It's good to see a nice healthy balance sheet, of course.
It's good to see the extra $80 million dollars, of receivables coming to our cash balance in the last couple of weeks here. Our copper production was up 5% over last quarter.
It's good to see our C1 costs come down again to just over $0.70. It's great to see the procurement -- annualized procurement savings continuing to increase, and we are targeting $40 million by the end of the year.
I think it's important that we rewarded shareholders through interim dividend, and we have completed $19 million of the buyback program. It's also exciting to see Carrapateena progress with box cut complete, site infrastructure now in place and the decline of some 70 meters now down the hole.
Looking forward, a couple of key releases coming up is the completion of the Carrapateena pre-feasibility study in November and then the Prominent Hill resource reserve and updated mining strategy in November. So with that, I might wrap it up and open it up to questions.
So operator, can you please remind people on how to ask questions?
Operator
[Operator Instructions] Your first question comes from Michael Slifirski of Crédit Suisse.
Michael Slifirski
I've got 3 or 4 pretty simple ones, I hope. First of all, the power cost period -- sorry, the power contract period ending in next year that you alluded to in your presentation, can you talk a little bit about the implications of what you're seeing in the market now compared to what your contracted is, and what you might expect in terms of any adjustment?
Andrew Cole
Michael, very good question. Look, I'm going to answer this at a high-level then ask Luke to give you a bit of an update on the process we've got undergoing with the power strategy.
We are putting a power strategy in place and we've touched on this the last time we talked on a call like this. That power strategy is looking holistically across Carrapateena and Prominent Hill, as these things all need to be connected together as you can probably appreciate given the type of market here at South Australia.
There is a lot of focus at the state level and the federal level on power and power stability and pricing in the states. So we've been very encouraged by that level of focus.
We're going to continue working with the state on that. I think I'll just ask Luke to talk through a little bit about the process we're undertaking with renewing contracts and the like for Prominent Hill and establishing Carrapateena.
Luke Anderson
Yes. Look, we've started an expression of interest.
We've gone out fully to the market fairly broadly in terms of various types of power options. We haven't tried to limit it in any way.
We haven't got visibility on the outcome of that. We should certainly have that coming into this quarter and should have a better feel for, as you alluded to, that pricing environment by the end of the year, I think.
Andrew Cole
I'll just add to that, Michael. I think whilst the power outage has been very negative, of course, and damages our ability to produce concentrate, the one upside of this is that it's shone a very bright spotlight on power in the state, from a state and a federal level.
And many people worked together to actually put stability and competitiveness into this market. So I think that from that perspective, it's actually quite a good thing.
So once we get some transparency on what that strategy looks like and what the commercial rates are going to look like, we're moving to fees right now, we'll be able to give you some update.
Michael Slifirski
Okay. Secondly, with respect to QPs now having hedged copper each period, so is it right that the only QP exposure is limited to gold for that period?
Andrew Cole
Correct, yes.
Michael Slifirski
Okay. With the additional drilling you've done at Prominent Hill, can you talk a little bit about how we should be thinking about the reserve and resource changes that you'll be announcing in November?
Andrew Cole
You're asking me to sort of preempt the answer here a little bit, Michael. Look, we will -- with the resource and reserve statement, it won't just be a resource and reserve statement.
We'll probably do something a little bit more substantive to that, talk about what our mining strategy is because there's a number of other moving pieces in this. So look, I might just push that back, if you don't mind.
I'll answer it more completely in November when we come out. There has been a lot of extra resource reserve drilling.
There's been additional resource definition drilling and we've removed all of the arbitrary constraints that used to exist when we define the resource model. So you will recall an arbitrary RL cut off at debt, which we've now stripped out, so it will change.
Michael Slifirski
Okay. I'll wait for that then.
And then finally with respect to Prominent Hill in milling rates. I guess in the past, we saw quarterly annualized rates around 11 million tonnes, and more recently, it seems to be substantially less that, but I guess there's been maintenance issues, the girth gear issue, the rain issue and so on.
So what are you actually expecting with the ore mix that you've got now is sustainable until you get into the gold only ore period. Because if I recall, I think you've talked before about your expectation that when you had a dominant gold on the ore mix, you could sustain a 9.5 million tonne per annum rate, but that seems to be the rate you're operating at currently with a predominant copper ore mix.
I'm just interested in -- whether you're thinking it's changing or whether my recollection might be a bit skewed.
Andrew Cole
Michael, I think the last 2 quarters, we've had some issues in the plant, if you probably recall. So the girth, yes, certainly impacted our throughput rate.
And it wasn't just the time we took the plant down to replace the girth or fix the girth gear. The ramp-up as we work that girth gear in place, shut it down 12 hours, 24 hours, fully open in 3 days, kept checking it, absolutely impacted our throughput rate.
So then, of course, we had a couple of days of power in the last quarter, we're going to have that same issue again this quarter with power being out 14% of the quarter already. So I wouldn't use the last couple of quarters' throughput rate to extrapolate out.
There's been a couple of exceptional items in it. But you do -- as you rightly point out, once over the next -- in a few years' time when we start to process more harder gold ore, we will start to see the rates come -- throughput rates come down to those that we previously published as a result of the gold trial.
Michael Slifirski
Okay. So -- but are you still confident when you have that predominantly gold on the ore mix you can sustain 9.5 million tonnes?
Or is my recollection around that number wrong?
Andrew Cole
Yes, Michael, it's possibly. The work we've done to date is still indicating that the gold only throughput rate will be around that 9 million to 9.5 million tonnes rate.
Obviously, we've got a lot of work and a long time to go before we get to that processing configurations. But as Andrew said, there's been a lot of abnormal [indiscernible] the last 2 quarters in the actual [indiscernible] result.
Operator
Your next question comes from Dylan Kelly of CLSA.
Dylan Kelly
Guys, just a follow-up question with regards to the expressions of interest that you've put out to the market for power supply. Just trying to quantify exactly what you've put that expressions for.
Is this for remote diesel site generators? Are you talking potentially building up like a renewable farm similar to some of your peers in the form of solar?
Just want to get an understanding of that. And secondly, just want to talk and understand a bit about how you're going to achieve guidance for the year just in terms of the current -- what you're seeing on the realm at the moment in terms of the feed?
Do you have some high-grade copper that you could effectively put through just at lower gold grades to come in at those throughput levels?
Andrew Cole
Dylan, I'll answer the second question first, then I'll ask Luke to answer the first one on the scope of EOI, if you like. So in terms of the -- Q4 for us was always going to be a relatively large quarter.
So we knew that, we've planned that and we've come to deliver that. We were going to be within guidance for Q4 pre-power, and I'm confident we are going to remain within guidance Q4 pre-power.
Some of the work that we did during the power outage absolutely helped us do that. So the couple of key things we did was manage to run the underground for most of that outage.
So we had temporary generation on-site, and we reprioritized work that got high-grade underground stopes that we were continuing to pool. And I mentioned before this circa-3% type stopes.
We've got that now sitting -- a lot of that's sitting on a lot of the line pads, which is being preferentially pushed into the processing plant. So that certainly helps.
And then we have also started a pre-crush trial stage. So this is a mobile crushing unit sitting on the ROM crushing some material before it goes into the crush circuit.
And what that does is it helps speed up, if you like, the throughput through the primary crushing stages. Bob do you want to that.
Bob Fulker
Now the big one is the underground and what we've been doing through that short period. So we had grown the underground ROM stockpile deposit and subsequently the grade of the ROM.
Possibly -- obviously, not necessarily our target but November and December is going to be big months [indiscernible]. The portion did actually [indiscernible].
Andrew Cole
Yes. So look Dylan, just to close that before I hand it to Luke, pre-power outage, I think it's fair to say we'll be shooting for the top of the guidance.
Now we're not shooting for the top of the guidance, so there is some impact that we comfortably see in the guidance. Luke, you want to answer the scope of power?
Luke Anderson
Yes, thank you Dylan. Look, the scope of the expression of interest process is very open.
We haven't tried to constrain the process because we're interested to sort of hear all the options out there. We are seeing some interesting ideas but it's still pretty early.
In terms of on-site diesel generation, you can certainly sort of benchmark, and that is pretty expensive so it's sort of would be hard to see that as being a solution in its own right. It may support an alternative, but in its own right, it's a pretty expensive option.
Dylan Kelly
Okay. So do you -- can you give us any understanding of where this might sit then because considering that you're stuck with ElectraNet in terms of existing supply and trying to work with a third-party to provide some sort of on-site backup power?
Or is this going to be generating your own low-cost source yourselves? Or is it just too open at the moment to really give us any kind of understanding of how you're thinking?
Andrew Cole
Yes, look, it's pretty open. I'd expect we're not going to divorce ourselves from the ElectraNet power supply.
I think anything we look at might supplement that, but it's still early days.
Operator
[Operator Instructions] Your next question comes from Hayden Bairstow of Macquarie Group.
Hayden Bairstow
Just a couple for me. Firstly, just on the underground sort of just in the quarterly talking about dumping ore at the base of the pit to sort of accelerate underground ore production for the quarter.
Is that just largely in response to trying to drop the copper grade up a little bit in the last quarter to hit guidance given what's happened with the power outage? Or is there something more to it in terms of the blend of ore mix or anything like that?
And then secondly just on the working capital move, I mean you ship more concentrate than you produce. So just wondering whether the receivables actually went up so much given most of the weather impacts were actually in August and July, not September?
Andrew Cole
Let me look at it into the second question. In terms of the third decline [indiscernible], this is not a new thing.
It's been planned for a while so it's actually a long-term planned ventilation shaft, not an ore extraction route. It's just that while we are building it, we will go and use it for ore extraction.
So I don't think of it necessarily pooling in tonnes of haul footage, it just gives us -- it's part of the ramp-up to the 3.5 million to 4 million tonnes per year, and it's part of the phased development. So Luke, do you want to touch on...
Luke Anderson
Yes, look, I guess the -- we've sort of been -- sort of running a little bit behind on concentrate shipments for a while and the weather impacts have sort of delayed that even further. So if I'm understanding the question, I mean, we just had a lot of shipments really in late August, September, and we get the delay of that receipt into mainly October.
Andrew Cole
So Hayden, if you go to the cash generation slide on the pack that we sent out, there is a chart there showing weather impact. And we're really just talking -- so we lost 1/3, I think, of August in terms of ability to take on from Prominent Hill across to the rail sighting.
So -- and that sort of unwound through September and more recently into October. It's really just [indiscernible] between getting the tonne out and getting the cash in the door.
Hayden Bairstow
Okay. So there's not been any change in payable terms or, call it, customers you're actually selling to?
Andrew Cole
No.
Bob Fulker
No, this is entirely to do with trucking. So the road between Prominent Hill and the sighting is over 100 kilometers that's unsealed.
And as you actually will appreciate, I mean, you've seen sort of terrain. When it gets wet, you can't drive.
That's the reality of it. So whenever it rains up there, we suspend trucking.
And we've lost 16 days, I think it was, through the quarter. So all it does -- I mean, our [ph] inventory keeps building until we get a period that we can actually take it on across to the rail sighting.
And mostly, it's fairly dry up here, so this is not an issue for us. It just so happened the last quarter has been, I think, the wettest -- one of the wettest quarters on record for the space.
So I assume probably we need to deal with.
Operator
There are no further questions at this time. I'll now hand back to Mr.
Cole for closing remarks.
Andrew Cole
Okay. Well, thank you very much.
As usual, if there are any questions that we haven't answered to your satisfaction or you want more detail or you think of anything afterwards, please reach out to Tom. And Tom will organize with the relevant people inside the company to help you with your questions.
So thanks very much for your time.