WASHING SOLUTIONS
Features of McLanahan log washers
Drives – All McLanahan log washers employ a V-belt-drive , single-input , dual-output gear reducer , which can be uncoupled from the log shafts and frame for maintenance . Log shafts – The McLanahan log shaft design handles large tonnages with less power and less water . Wear collars are utilised at the feed-end flanged connection to protect the connection bolts , bearing and bearing housing from wear . Paddles – The paddles are designed to optimise the combination of hardness and ductility to maximise abrasion resistance . Spray bars – All McLanahan log washers come standard with a centre spray bar to provide a final rinse before the material is discharged from the washer box . Wash water from the spray bars carries the dissolved clay or organics to the feed end of the machine , where it is removed with the overflow . Submerged bearings – McLanahan submerged rear bearings feature seals that keep water and even the smallest particles from reaching the bearings . Optional clean-out doors – McLanahan supplies drop-bottom doors in the bottom of the log washer box for easier cleaning during maintenance or seasonal shutdown . Slope adjustment – McLanahan offers either mechanical or hydraulic slope adjustment to provide additional washing for removing tougher materials .
The log washers McLanahan builds today
function the same way as Samuel Calvin ’ s original machine , but they look quite different . “ For one , the shafts are no longer made of tree logs ; they have been replaced by an all-steel construction . The paddles on the shaft have also been updated through the decades , as have the position of the paddles and shafts . These design changes helped improve the wear life of the log washer and its components .”
“ It was quite an invention , and we still manufacture it ,” said Michael McLanahan , Chairman of McLanahan Corporation ’ s Board of Directors and Samuel Calvin ’ s great-grandson .
Another design update to increase longevity was the change from box and thimble outboard bearings to roller bearings , which are easier to maintain and improve machine operation . “ It is a good design that has evolved through several
The original Log Washer was actually invented in 1891 by Samuel Calvin McLanahan , the second generation of family ownership of McLanahan Corporation , to remove clay from gravel , various types of ores and crushed stone to improve the quality of the material iterations over the years ,” McLanahan said . “ We ’ ve worked closely with our customers to improve the design based on their experiences operating them in the field .”
While Samuel Calvin originally invented the Log Washer for iron ore , it was soon applied to other materials , such as gravel , rock and crushed stone . More than a century later , log washers are still a staple in both the aggregate and
minerals processing industries for removing tough clays and improving final products . “ The log washer was not a one-hit wonder — it carried on throughout the years and is still needed . We ’ re still selling them today to do the same thing , just in a better way — more efficient and lower cost to the operator ,” McLanahan said . “ It ’ s a good , sturdy , long-lasting machine that ’ s a good investment for those companies that need to remove clay and organics from their ores .”
A predominant use became phosphate mining / processing in the southeast US , very notably in Florida . Log washers continue to be used there .
McLanahan told IM : “ Today there are several manufacturers globally that offer varying washer designs that call their machines a log washer . The success of these machines varies depending on the design and orientation of the paddle shafts to each other , paddle design , paddle shaft length , speed , and installed slope or position .”
While many more units are used for washing gravel and crushed stone aggregates , globally McLanahan log washers have been sold for washing a wide variety of clay contaminated hard rock ore types including magnesite , bauxite , calcium carbonate , silica rich iron ore , marble , tin ore , manganese ore , gold ore and nickel bearing ores .
Recently a 46 in x 35 ft Super Mudmaster Log Washer was sold to a mineral processing company for washing heavily clay laden bauxite ore in South America . The machine is part of a crushing , screening and washing system that allows them to produce a clean rock bearing bauxite ore at 175 t / h ready for shipping to an alumina refinery .
Terex focuses on recycling
The Terex Washing Systems smaller Powerscrub PS 60R and larger Powerscrub 200 & 200R modular log washers it says “ are designed to produce cleaner material at a faster rate . Specifically designed to work in the recycling industry , their versatility and design enables them to be easily adapted to work in gravel applications ” but they also have applicability in certain industrial minerals markets .
The larger design can achieve 200 t / h and consists of a trough and two spiral axles running counter to one another with exchangeable blades which intensively mix the feed material . Water used in this process is recirculated to a water treatment facility . A built-in agitation system excites lighter particles , causing them to float and in turn discharge via the adjustable water exits on the water discharge side . Optional dewatering screens can be fitted to either end of the machine . It is specifically designed to work in recycling applications to separate
The Terex Washing Systems smaller Powerscrub PS 60R and larger Powerscrub 200 & 200R modular log washers it says are designed to produce cleaner material at a faster rate and are specifically aimed at the recycling industry
contaminates form saleable material . A 12 x 5 dewatering screen removes excess water from material before final screening plus a 6 x 2 dewatering screen separates lighter particles .
The AggreScrub™ 150 plant it says is particularly suited to the C & D recycling market . Key benefits for customers include the improved wear characteristics , reduced costs , and the ability to effectively scrub aggregates and float out clays / silts / lights ( wood / plastics ) on one chassis . In addition , there are also a number of paddle options available depending on customers ’ needs , including the traditional hard wearing AR blades in 15 and 30 mm variances as well as a new high manganese steel option .
IM
54 International Mining | OCTOBER 2020