| First developed in the goldfields of the state of | | | | tossed out. The cradle must be placed on an |
| Georgia, the rocker was an important gold mining | | | | inclination while being worked, and under the influence |
| tool. At the very dawn of the Gold rush to California, | | | | of the continued side-to-side rocking the dirt is quickly |
| the rocker box also known as a cradle was perhaps | | | | disintegrated, passes down through the hopper |
| the most used piece of gold prospecting equipment. | | | | grizzly and the water and the undersize fall down |
| For a time it was perhaps even more important that | | | | onto the canvas apron which saves most of the gold |
| the gold pan. Mostly this was because the miner | | | | and places the remainder at the head end of the |
| could make a rocker for himself in the field from | | | | trough. From the apron it is conveyed to the inner |
| rough sawn lumber cut in the forest. They are also | | | | end of the cradle floor (the sluice box like section of |
| easily portable. Rocker boxes were also popular | | | | the rocker), from which it flows over the riffles, or |
| during the Klondike gold rush for working the hillside | | | | bars, and out at the mouth. Riffles, canvas, blankets, |
| placers that were far above the creeks. | | | | corduroy, burlap, or cocoa matting with expanded |
| The 'rocker' is a box with a hopper about 3 to 4 ft. | | | | metal have been used to cover the bottom of the |
| long and 1 to 2 ft. wide, sloped like a cradle, and is | | | | trough and all have met with varying degrees of |
| mounted on semicircular pieces of wood and worked | | | | success in saving the gold. The combination of cocoa |
| by a, handle to give it a side motion; and it is also | | | | matting covered with expanded metal lath has |
| inclined so as to carry the material down to the lower | | | | proven to be quite effective for most gravels. The |
| end, which is open. At the upper end is a small | | | | frequency of cleaning up depends on the richness |
| hopper that may be removed and which has a | | | | and character of the gravel, but clean-ups are usually |
| sheet-iron bottom perforated with 1/2 -in. holes. | | | | necessary two or three times a day. The hopper is |
| Under the hopper is a canvas apron or tray inclined | | | | taken off first, then the apron is slid out, and washed |
| toward the head of the box but touching neither end | | | | in a bucket or tub containing clean water, and finally |
| of the hopper-box. Several wooden riffles are placed | | | | the gold is collected with a spoon from behind the |
| across the box. The material is fed into the hopper | | | | riffle bars, and panned out. |
| and screened through by water poured on top; the | | | | The rocking motion used should be sufficient to keep |
| lighter material is carried over the end, while the | | | | the gravel disturbed, allowing the gold to settle out, |
| riffles in the box catch the gold and magnetic sand. | | | | but a too vigorous movement will cause a gold loss. |
| This concentrate is cleaned out and panned at the | | | | The gravel bed should be shifted slightly with each |
| end of the operation. The rocker is used for the | | | | motion and should be evenly distributed across the |
| same type of work as the gold pan in that it is | | | | trough. Generally speaking, the rocker is not known |
| mainly a prospecting tool. A man is able to wash 3 to | | | | for its ability to save fine gold, but with careful and |
| 5 times more yardage than with the gold pan, and | | | | expert manipulation, decent fine gold recoveries can |
| the use of the rocker eliminates much of the | | | | be achieved. Tailings from both rockers and sluice |
| backbreaking strain of continuous panning. On the | | | | boxes should be occasionally panned to check for |
| other hand, the easy mobility of the pan as a | | | | gold losses. When gold is found near the lower end |
| prospecting device is lost. | | | | of the rocker or sluice box, the potential for losses |
| So why might a modern prospector be interested in | | | | should be investigated. |
| building his own rocker box? The principal use of a | | | | Because there is no one "right" design for a rocker |
| gold rocker is for mining small deposits where water | | | | box, I am not actually presenting specific plans, but |
| is scarce. It is not really a desert device and it does | | | | on my website I am giving you the information you |
| use some significant water, but not nearly as much | | | | need to plan, design and build your own rocker box if |
| as a sluice. In a rocker, gravel requires about three | | | | that's what you decide to do. My recommended |
| times its own weight of water to wash it. So | | | | design for a rocker is to start buy building a sluice |
| perhaps the best use is in streams and waterways | | | | box 40 inches long, 16 inches wide on the bottom, |
| with very little water - where some water is present, | | | | sloped like a cradle, and with rockers at each end. |
| but not enough to run a sluice box. If enough flowing | | | | The hopper would be 16 inches square and 6 inches |
| water to run a sluice is present, a sluice is faster and | | | | deep, with a sheet metal bottom made of |
| easier to run than a rocker. The rocker is only a | | | | perforated steel with 1/2-inch holes. This hopper box |
| primitive machine, having a capacity but one-fifth as | | | | needs to be designed so it can be removed for clean |
| great as that of the sluice box, but because it is | | | | up. A light canvas-covered frame is stretched under |
| cheap, requires but little water, and saves a high | | | | the hopper, forming a riffle. Square riffles of wood or |
| percentage of coarse gold, the rocker will continue to | | | | steel are placed across the bottom of the sluice |
| be used in many districts. | | | | portion of the rocker. Curved feet are placed |
| The operation of a rocker consists of shoveling | | | | underneath the sluice portion of the box to allow it |
| gravel onto a screen or grizzly, pouring water over it | | | | to be rocked back and forth. Historically, rockers are |
| from a dipper, and at the same time giving the | | | | built of wood, as the early prospectors built them. |
| device a back-and-forth rocking motion. The grizzly | | | | However, there is no reason that a rocker could not |
| retains all the oversized stones, which are removed | | | | be built from sturdy heavy gauge sheet aluminum. It |
| by hand when they have been washed clean. The | | | | would be much lighter that the wood version. |
| operator briefly examines the oversize rock to be | | | | Remember that wood also absorbs water, and water |
| sure no large nuggets or gold specimens are being | | | | logged wood is much heavier than dry wood. |