| Show manpower man power and plant efficiency by LETSON the personal equation horsepower management eff efficiency ici ency although the methods of computation for reducing manpower into horsepower are not at all complicated it appears that we often forget the cost so long as we get the result horsepower seeing seems to be the easiest term for most people to comprehend nence I 1 will briefly try to fix its value in the minds of those who have forgotten but if anyone happens to use the term kilowatt all you have to do is to remember that it is almost exactly one and one third horsepower there is a growing tendency to make the Effi efficiency clency engineer 1508 hobart build nl US san francisco kilowatt the standard term for the unit measurement of power the elementary explanation of one horsepower is the power required to raise pounds one toot foot high in one minute or conversely to raise one pound feet in one minute or pounds ten feet high in a minute and is referred to as foot pounds equaling one horsepower thus t find the horsepower of any given motion multiply the weight in pounds by the height in feet divided by the time in minutes required for making the lift and divide by equaling the horsepower example hoist three tons feet in two minutes foot 2 pounds per minute dividing foot pounds by equals horse power that is very simple but it mean so very much to the manager the president the stockholders or the bookkeepers till it can be brought down into dollars if you are buying coal at 10 per ton de livered in the boiler room and utilized under average mine conditions for hoisting and pumping you are probably paying eight or ten cents per horsepower hour if you are using electric power you may be paying around one or two cents per horsepower hour if you are not wasting va sting any it is not my intention to go very deeply into these figures because they are different e nt in every mine particularly the standby costs the waste and the labor etc but I 1 am trying to reach a figure to use as a basis for another line of thought for that reason I 1 am going to use two cents per horsepower hour and if any one has power at one cent they can divide these figures in the middle if the cost is greater make the cnance accordingly t three ton load in ten minutes using the 2 cent basis to find the cost of f hoisting the three ton load in two minutes we find that it would require 12 horsepower hours every minute or practically horsepower hours or 5 cents to hoist the three tons if at the end of the month you have hoisted tons your actual power work done is 50 but the power bill or fuel bill is probably considerably more depending upon the efficiency of your operations 1 having reached a point where we can assume that horsepower costs 2 cents per hour per horsepower now let us see what manpower costs cost of manpower to equal a horsepower a man must lift pounds one foot in a minute for illustration we will suppose that a miner with a shovel was loading a mine car and his average shovel full no 2 shovel held fourteen pounds every time he puts a shovel full into the ore car he raises this fourteen pounds four feet and performs fifty six foot pounds of work to load this car with one ton of rock or ore he shovels shovels full to a height of four feet and performs foot pounds of work but he doit do it in one minute he does it in ten minutes it if it takes him ten minutes to load the car therefore his power capacity is foot pounds in one minute or almost exactly one fortieth of a horsepower in other words it takes him forty minutes to raise as many foot pounds as a horsepower I 1 1 minute assuming that the laborer draws a wage wage of 50 cents per hour for performing ones one fortieth of a horsepower in work we find that manpower at 20 per hour equals the same number of foot pounds of work that costs two cents in electric power thus at 4 a day a laborer works five days to do the work that one horsepower does in one hour for 2 cents advocates mechanical power it may not be practical nor possible to perform power shoveling everywhere and I 1 am only using this as a measure of the e power capacity of a man but there a are e many things that are done by manpower that could be done by mechanical power which would make that proportion of s saving av and in line with that thought thong lit it might be pertinent to inquire why do you struggle so hard to take up a thirty second of an inch of lost motion in a machine that costs 2 cents per horsepower hour and let a workman at 20 per horsepower hour have a mile of lost motion the lost motion is wearing fatiguing and expensive why my do you pipe cold water into a compressors pres sors jackets and force a man to walk clear to the shaft for a drink why do you force a man to carry or pull by hand his timbers and tools into a and convey the ore to the mill on a conveyor why do you build your waste dump by having a man shove a car over a croo crooked ked uneven track instead of using a modification of the scraper or aerial tram we can always load gravel cars from a gravel pit for about two cents a yard picking up the gravel from a radius of feet and depositing it in one place would it be such a big step to reverse the situation and take the waste from the collar of the shaft and drop it over the dump why do you let a man run a hand saw through the mine timbers when they can be cut to length by power why do you let a workman bore holes in the wall plates with a hand boring tool when a power boring tool can do it in one fortieth of the time why do you have a man carrying tool steel to the blacksmith shop when it could be sent down a chute or conveyed if the equipment were laid out right why do you have a dozen men changing a cage or skip when a crawl and an air or electric lift could take the weight and run it back in the gallows frame why do you put an electric light over the managers doorstep and require workmen to crawl down a slope with a candle why do you allow a man to come out 0 of a dead end for air when 2 cents an hour would fan all the air he needed and I 1 might go on and ask a hundred more questions and not touch upon all the conditions that are so varied at different mines every one of you can probably make an excuse I 1 do not doubt that but there is some difference between making excuses and making good |
