Rock Products

MAR 2013

Rock Products is the aggregates industry's leading source for market analysis and technology solutions, delivering critical content focusing on aggregates-processing equipment; operational efficiencies; management best practices; comprehensive market

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CRUSHING BREAKING Your Big Break: Crushing for Success ��� Changing speed is easy, but adjusting the stroke is more difficult. ��� - Mark Krause To Mark Krause, operations manager with River Aggregates, increasing crushing ef��� ficiency might necessitate a shorter���term view of the operational life of crushers, although some adjustments can be made to extend their lives and maximize their throughput. ���We���re asking a lot more out of our equip��� ment,��� he said. ���We���re asking it to be more efficient, and we���re asking smaller pack��� ages to do more. Do we keep in mind that when we do that, we���re more than likely shortening the life expectancy of that equipment? For instance, we probably ex��� pect a cone crusher to last 25 to 40 years. Today���s new cone crushers are probably 10��� to 15���year machines. There���s nothing wrong with that ��� it���s just a different mind���set.��� Krause says he is spending less up front because he is buying a package that���s more efficient, but it might not last as long as the old one. ���The other thing about crushers is, whether it���s a primary or secondary im��� pactor, make sure you���re using modern technology for wear parts,��� Krause said. ���There���s been a lot of work done in the past few years on ceramic and carbide��� embedded wear parts. The longer you can let those parts run, the more efficiently that crusher is going to run.��� Increasing the speed or replacing the liner are other simple operational changes. Ensuring that the crusher���s surge point remains full also costs less than purchasing a new crusher. ���If you���re going to get the most out of any tool, you need to keep it full,��� said Krause. ���Spend the money on the surge point and see if you get your desired outcome 38 ROCKproducts ��� MARCH 2013 that way; if you don���t, you can worry about buying a new crusher. But you���ve already spent the money that you���re going to have to spend on a new surge point anyway.��� Krause says that adding a surge bin is a low���cost way to keep the surge point full. ���They���re not big bins ��� maybe 40 to 50 tons. Some operators might use a 20��� to 25���ton bin and a belt or vibratory feeder.��� The entire cost is probably around $50,000, he estimated. ���Sometimes you���ll find that you can���t put the bin above the crusher, so you need to locate it a con��� veyor length away.��� Screening Helping Crushing While maximizing the efficiency of crush��� ing operations will definitely help plant productivity, improving screening effi��� ciency can also make a big impact on plant throughput in most operations. ���There are a lot of screens that were in��� stalled 10 years ago for certain applica��� tions; the application has changed, but they haven���t gone in and changed the me��� chanical setup of the machine,��� Krause said. ���They're still using the same speed, same stroke, same everything.��� Changing speed is easy, but adjusting the stroke is more difficult. ���We have to be cautious that we don���t go outside the bounds of what the manufacturer sug��� gests the screen can do. You can���t have high speed and high stroke together or you might end up destroying the screen.��� Newer machines make it easier to add weights, allowing producers to adjust to different material often. Krause says the media has changed dra��� matically in the world of screening. ���There are all types of live wire screen deck today that incorporate rubber and wire or urethane and wire in combination on a deck where, traditionally, we once used wire cloth. Then rubber decks and urethane decks came along: rubber for dry applications, urethane for wet appli��� cations,��� he said. ���Washing has been so misunderstood,���

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