O Polydeck ajuda as mineradoras de ouro de Klondike a obter grandes ganhos de produção

A histórica corrida pelo ouro que eclodiu em 1849 no estado da Califórnia, mais tarde saltando para o território canadense de Yukon, não se tratava tanto de ficar rico, mas sim de ousar correr riscos - tentar, fracassar e tentar novamente. Naquela época, o empreendedorismo americano ganhou grande impulso. Avançando para o presente: A série de televisão do Discovery Channel Corrida do Ouro atingiu o ponto alto por seis temporadas, sendo o programa de maior audiência da rede.

Dave Turin, a principal cast member of the TV series ‘Gold Rush,’ checks a feed box at the Klondike gold operation. (Photo: Gold Rush)

Dave Turin, um dos principais personagens do programa, descreveu a série como a saga de trabalhadores da construção civil sem sorte que enfrentam todas as adversidades na esperança de se dar bem no negócio do ouro. "Ela fala do 'espírito americano', de arriscar - e sair do sofá, calçar as botas e começar a trabalhar, independentemente do risco", disse ele. Turin faz parceria com Todd Hoffman, membro do elenco, fundador e líder da 316 Mining, que opera em uma área de reivindicação na região de Klondike, em Yukon, no noroeste do Canadá.

"Essas chances não foram fáceis, pois não tivemos muito sucesso nas primeiras temporadas, mas continuamos assim e evoluímos, como acontece com qualquer empresa iniciante", disse Turin. Quanto à temporada atual, ele disse: "Estamos capturando muito ouro".

The successful evolution of the Gold Rush mining teams is due in part to the expertise and equipment provided by a number of the nation’s top mining equipment manufacturers. Among them is Polydeck. The company first got involved with Gold Rush in 2012 when providing the screen media, a frame system, and accessories for the top deck of a 5 x 16-ft double-deck vibrating screen.

During the current Gold Rush season, Polydeck conducted a complete screen performance evaluation for the 316 Mining team. These “value-added” evaluations, according to the company, often lead to greater screening efficiency by determining needed adjustments to screen speed, stroke and acceleration. The latter is combined with an analysis of the support structure, bearings, and other key components to help prevent excessive wear and potential equipment failures.

A Polydeck disse que adota uma abordagem única de visão geral para maximizar o desempenho da tela para seus clientes. Na unidade da 316 Mining, a avaliação do desempenho da tela e o ajuste fino subsequente levaram a um aumento estimado de 25% na eficiência geral do peneiramento para a equipe da Hoffman/Turin.

“Working with Polydeck is a great partnership. They continue to take chances on us—and that’s what our show is all about,” said Turin, who added that he first requested Polydeck screen media several seasons ago. “Back then, we put their media on the top deck of the wash plant that we called ‘Big Red.’ This season, we’ve got it on the plant we call ‘Monster Red,’ and we’ve doubled the production capacities that we had two years ago.”

Turin se familiarizou com Mídia Polydeck quando o instalou em sua empresa familiar de pedreiras e pavimentação, sediada no Oregon. "O que importa é a longevidade da mídia Polydeck. Ao contrário da tela metálica tradicional, podemos colocar o Polydeck e esquecer dele. O dinheiro que economizamos em mão de obra e trocas de telas metálicas supera em muito o custo inicial da mídia. É por isso que o queríamos para nossa operação de mineração de ouro."

Soluções direcionadas

Em 2014, a equipe da Hoffman/Turin fez um upgrade para uma tela maior de deck triplo, de 6 x 20 pés, e mais uma vez solicitou a mídia Polydeck. A Turin compartilhou seus requisitos específicos com os engenheiros da Polydeck, que recomendaram as configurações ideais de tipos e tamanhos de abertura para a aplicação. "Eles entendem nossa máquina, o que estamos extraindo e nos forneceram as aberturas certas para o nosso tipo de material", disse Turin.

O Polydeck forneceu Polydex painéis modulares de poliuretano e Rubberdex painéis modulares de borracha, bem como sistemas de estrutura e placas de desgaste lateral. Turin disse que a modularidade do deck significa que eles podem trocar um único painel de cada vez, se necessário, em vez de substituir o deck inteiro. O mais importante, disse ele, é poder trocar os painéis conforme necessário apenas na extremidade de alimentação, onde há todo o impacto e desgaste.

O novo Polydeck Armadex bolt-down rubber chute panels are installed on the feed end of the top deck. Armadex sections are steel-backed rubber panels that combine a proprietary blend of natural gum rubber with a high-strength/low-alloy steel plate backing, making it ideal for tough, abrasive applications. According to Polydeck engineers, Armadex panels are created using a Binary Injection Molding (BIM) technology, which is a proprietary Polydeck manufacturing method that produces 10 times the pressure normally used to produce compression-molded rubber. Poydeck said combining this process with premium natural gum rubber and HS/LA steel plate backing produces unprecedented strength, which results in longer wear life at lower costs per ton.

Hoffman said, “We’ve got the best wash plant in the Klondike, hands down.” His crew reported that over two seasons, they have put more than 800,000 yd3 of abrasive, quartz-filled material over the rubber and polyurethane decks, at an average of 250 yd3/h—running 24/7 from June through September each season. “The decks still look great and we’ve maximized our uptime and saved big bucks on maintenance and labor. For example, if we had used standard AR Steel plate on our feed end (vs. the Armadex), we would have been changing that out once a week,” said Turin.

Turin and Todd Hoffman (right), another cast member, say they are convinced the initial cost of installing polyurethane and rubber media panels and parts is significantly offset by reduced labor requirements and longer service life provided by the Polydeck products.

Desempenho em um panorama geral

Mike Garrison, a Polydeck product support specialist, has conducted hundreds of screen performance evaluations in the mining industry. He traveled twice to the Yukon to visit the 316 Mining site to complete an evaluation and offer solutions for greater efficiency. “We offer the technical assistance that goes beyond looking at screen media and examines the entire screening circuit—to make the circuit more reliable, to increase their recovery; and to minimize maintenance,” said Garrison.

Evaluations record a screen’s orbits; motor speed; any harmful deflections along the Z axis; material travel rates; and any movement of the support structure. It also examines a screen’s critical frequencies to help determine the screen’s optimal speed and stroke. Importantly, the final report includes any recommended adjustments to a screen’s operating parameters and/or media to maximize its operating potential in its particular application.

Within Garrison’s detailed report, an example of one of the major issues uncovered during the evaluation is that the combination of the screen’s displacement and acceleration was excessive for the bottom-deck apertures (openings) and was likely contributing to inefficient screening on the bottom deck. The level of acceleration was also causing body (Z) axis deflections along the bottom deck. Consequently, adjustments were made resulting in an 11% reduction in the displacement (stroke) of the vibrating screen. “This adjust ment boosted overall recovery and had an immediate effect upon overall efficiency,” said Garrison.

After fine-tuning the screen’s operating parameters, Turin reported that they saw a noticeable improvement in the bed depth and carryover on the bottom deck. “We have increased production to 280 yards per hour with very little carry over. Depending upon the quality of pay dirt that we run, our recovery rate is between 3/4- and 1-1/2-ounces for every hundred yards of material over the screen, which is a significant increase over last season,” said Turin. While initially skeptical of all the troubleshooting, Turin said the results achieved after completing the recommended adjustments has him convinced of the value of conducting periodic screen performance evaluations.

Ciência e sinergia

O desempenho ideal do peneiramento é menos uma questão de tentativa e erro e mais uma questão de entender a ciência do peneiramento. A equipe da Hoffman/Turin reconheceu que sua parceria com a Polydeck permitiu que eles "marcassem" seus requisitos e identificassem continuamente as áreas que proporcionariam o maior retorno. Em última análise, trata-se de menos riscos e maior recuperação.

Escrito por Carol Wasson, escritora freelancer veterana dos setores de agregados e equipamentos de construção.