Cotton Seed Distributors - Web on Wednesday

Mick Forster - Auscott Narrabri discusses how to prepare for picking and minimise quality downgrading and contamination

Mick, firstly, would you have some general comments, most growers are aiming to produce high quality cotton, what things can the grower do to improve the quality before picking?

From a ginners perceptive, mature clean seed cotton is much easier to gin than immature trashy cotton. Presuming all the normal agronomic practices have been done, the timing of the defoliation is critical to ensure the fibre is mature and the leaf has been removed. Cotton picker pre-season maintenance is important. Doffer and moisture pads and spindles must be checked and replaced. Good housekeeping all the year round is most important, things like irrigation tarps, bags and old clothing etc that blow into fields can be picked up by pickers and as a result you see them in the modules.

Then comes actual picking time. Again, I refer to good housekeeping because at the end of the day good housekeeping means low contamination which is most important. We look at contamination during the picking season around the module builder itself have rubbish bins and bags where employees can place their rubbish. At the induction of casual staff it is so important to impress upon them the importance of good housekeeping. It is amazing the amount of lunch wrappings and stuff like this we see in the modules, I’m not sure whether it is laziness or what, but nevertheless we see it there. Don’t throw dirty seed cotton into the module, that’s after the rakings, obviously you rake up what is obviously good cotton but if there is any dirt or rubbish mixed up with it, it should be disposed of as rubbish.

As far as pickers go during the season, regular checks on the head heights, pressure door settings, doffers, moisture systems and pickers doors. Clean basket lids really need to be checked regularly, no doubt about it, we see the striping in the modules when they come in and that’s a result of the picker lids not being cleaned regularly enough so you get that very fine fibre and trash content dumped into the module.

Are there any other issues during picking that come up?

Certainly module builders are probably the main source of contamination. They have oil contamination, hydraulic hoses break and again we can see the effects of that on the modules when they come in. with the dust from traveling – you can see spots of oil on the outside of the modules. Oil contamination is a very serious contamination because it is not actually detected until the actual dying process, well down the chain of the textile industry.

Another one I know you get occasionally is modules that may have had a fire in them. Whether that fire is still going or not, what should be the procedure if the grower has or suspects that there has been a fire in a module?

That’s a most important one. You can well imagine the value of modules in a module yard – nowadays we can have up to 4,000 modules in them, if we get a big wind and a fire in a module it is almost impossible to put them out. Needless to say we are talking tens of millions of dollars of damage. We are very, very conscious of that. We usually see most fires at the beginning of the season. I think that either comes back to the crops not being quite ready and the machines not being set up properly and if we have got bent spindles or pieces of wire for instance may be picked up in the machines, that spark will end up in the basket and from there into the module builder and that will take days and days for it to ultimately burn out. Once it does burn out we will have a big problem on our hands in the yard. Again, the most important thing, if there is a suspect module, leave it in the paddock, and contact the ginner. We will take the appropriate action from there. Really, it should be left out in the field until such stage that we are sure there is no fire danger.

How long would you need to leave it there?

Two or three weeks are certainly not uncommon. I have seen it that period of time, when it is being lifted onto the truck that’s when the air gets to the fire and you have a fire on your hands. That certainly has implications for the grower, the ginner and everyone else.

After picking now, is there anything that growers need to do? They have picked the cotton, got it into modules, from that stage onwards what are the things they need to do from there?

Things like module pads, we do get whole cotton plants come in underneath the module. Obviously the module has been built in or on the edge of the paddock and when we do get the complete plants running through the gin, that can just block up the pipeline through the way and that can cause us a lot of problems. Of course we are getting bark and other contamination problems with it.

You must remember with infield loaders they need a metre or so either side of the module so they can straddle the module. If modules are built where they can’t be picked up properly we end up with broken modules in the yard. We really can’t protect them from the weather, you can’t cover them, the loose cotton – a lot of the cotton will blow away. Somehow we have to get it onto the module feeder and gin. Small things like that. Well built modules, good module pads, module covers again are just an important thing and as far as I am concerned there is only one module cover and that’s the tailor made fitted cover which runs down at least a metre if not more down the sides. Whilst they may sound expensive first up but if they are amortised over a five year period they are relatively cheap, particularly if we do get a wet season and you have an inferior quality cover on the downgrading is far superior to the cost of the module cover.

Moving on to contamination, what are the main sources of contamination in Australian cotton, we have a reputation for having reasonably clean cotton but I’m sure there are some contamination things we need to be more careful of?

Yes that’s true, our reputation is beginning to dwindle a little. On the recent study done by the CSIRO, where they surveyed the thirty-odd mills in Asia, there were certainly concerns about our contamination and our reputation may not be as good as it was so we have to work hard there. The natural contamination are the things like bark and that comes back to poor picker and stripper settings, grass, obviously poor farm hygiene, synthetic fibres, the most serious one no doubt strands of fibre from irrigation tarps and patches from repaired tarps, lunch bags and clothing that will find itself in the gin and if it wraps around a rotating shaft – and you can imagine there are lots of rotating shafts in the gin – it can rotate and sit there for days or weeks and we can quite literally contaminate thousands of bales just from one piece of synthetic fibre.

Hydraulic oil is another serious one, mainly due to maintenance of pickers or builders and pickers and when we see that we really should dispose of that cotton and not leave it in the module. Grease from picker heads is another common one where I think again it is basic good housekeeping practice by the mechanics that maintain the machines on a day to day basis in the field. Pieces of metal, while they do a huge amount of damage to the gin, some smaller pieces actually do get through the system and end up in the spinning mills and that can cause severe damage to the mills.

What other things should the grower inform the gin about before module delivery and ginning and the interaction between the grower and the ginner?

Burrs are something that can cause a lot of problems in the gin. If we have Bathurst or Noogoora burrs they get through most of the pre-cleaning process and end up in the gin stand itself. They cause a tagging at the gin stand and friction of the saws will ultimately cause fire, if we know about it we can keep an eye on the gin stands and make sure we regularly clean it more often than we normally would. Obviously large pieces of steel can do huge amounts of damage to the gin, not only in actual costs of spare parts but the actual down time. Some of those repairs can’t be completely done until after the season. Any suspect spare parts or lumps of steel, most important that we know about it and we will do our best to find it. Pieces of wire wrap around the revolving shafts and causes fires. Traps, clothing, bags are contamination that I have already discussed. Just good housekeeping right around the farm.

Moisture, anything over probably 10% moisture in the module we really need to know about so we can keep an eye on the temperature moisture levels in the module yard as well as during the ginning process. If it is too moist ultimately you will get spotted cotton and that costs a lot of money and excessive green leaf similar to the moisture problem.

What are the things the gin can do to improve quality and what are some of the things they can do to reduce quality?

It is a bit of a fallacy to say that cotton gins can improve quality. Basically the colour, length, strength and micronaire are inherent in the seed cotton that arrives at the gin so we can’t do anything about that. The function of the cotton gin is to extract as much of the leaf and sticks before separation of the lint from the seed. That’s from the module feed to the extractors. Then we separate the lint from the seed at the gin stands and then go into second stage cleaning of the lint itself through the lint cleaners. Following that the lint goes into the press and is pressed into bales for storage and storage purposes.

The ginning process can optimize the value of the seed cotton by ensuring that the optimum amount of trash is removed from the seed cotton without losing too much fibre in the process. In other words it is a balance between leaf penalties and lint out-turn.

The main damage that can occur is neps. The more machinery that the seed cotton has to go through, the greater amount of neps that will be created. The maturity of the fibre has a great bearing on neps. The more mature the fibre is the lower the nep count, obviously if we have immature fibre we will certainly see a lot more neps.

To damage the fibre length and strength takes very high temperatures and I don’t think that any cotton gin in Australia will be capable of doing this because of the temperature controls that are installed in the gins and the fact that gas is very expensive and we only use it as much as we really have to. So basically a gins job is to maintain the quality of the fibre that comes into the gin and do our best to get the ultimate dollar return for each ton of seed cotton delivered.

Would you like to summarise some of the things we have talked about?

Further Information:  Robert Eveleigh, John Marshall,  Craig McDonald or David Kelly