Minelab's Eldorado Mk Ii
By Reginald G. Sniff
From Page 19
August, 1991 issue of Lost Treasure

One aspect of treasure hunting I have found to be extremely exciting is nugget hunting. Finding a gold nugget and watching it glisten in the sunlight is something to behold. Whenever I have the opportunity, I go to a location in Arizona called Rich Hill. Over the years, people have found nuggets the size of potatoes on top of this mountain in an area rightly known as "Potato Patch."

I had just made a spur-of-the moment decision to take another trip to my favorite site in Arizona before I received Minelab's Eldorado MKII from Wilma Beaumont of Down Under Treasures. Receiving this new detector for testing came as a pleasant surprise. The site I was planning to visit could easily be called Minelab country because of all the Minelabs in use there.

The Eldorado MKII is one of the new detectors developed by Minelab Electronics Pty. Limited of Australia. Like the well-known GT 16000, the Eldorado MKII is designed to find gold. That's not to say that Minelab instruments can't be used to find coins or relics because they can, and are, and do an excellent job of it.

In the case of the Eldorado MKII, the frills have been removed, leaving a workhorse of a detector. Unlike the GT 16000, there is no discrimination feature or automatic ground balance. Instead, the Eldorado MKII is a very deep-seeking detector equipped with all the necessary features and priced in the range of the cost-conscious nugget hunter.

Operating at a frequency of about 8 KHZ, the Eldorado MKII comes with a standard 8-inch DD widescan coil. The bright yellow control housing has three controls and two switches.

The adjustable controls are familiar-a 10-turn ground balance, a volume, and a threshold control. Instead of a sensitivity control, the Eldorado MKII has a two-position selector switch marked normal/difficult. Depending upon the ground conditions and experience, an operator can select the mode that works best for him or her. The greatest sensitivity is achieved when selected to the normal mode. The second switch found on the unit turns the detector off and on.

First Impressions

The assembly of the Eldorado MKII was extremely easy. In fact, the hardest part of the whole assembly was the re-installation of the battery cover after installing the eight AA batteries. The battery compartment, located on the bottom of the control unit, is designed to eliminate any detector damage should a battery fail and leak. Once the detector was assembled and the operator's manual read, I was ready to test the new instrument.

One indication of a detector's ability is an air test of objects. A quick air test of the Eldorado MKII displayed this detector could detect my 1.6 grain nugget with a weak but deliberate signal. The real test, however, is in how it performs in detecting targets in extremely mineralized ground. Fortunately, my hometown has just such conditions. Taking the new detector, a couple of different size nuggets, and a couple of hot rocks, I headed outside.

The Eldorado MKII was very easy to ground balance to the local conditions. After all the controls were set for comfortable signals, various targets were checked to get an idea of the response characteristics of the Eldorado MKII.

Careful checking of different-size nuggets indicated the new detector could detect extremely small nuggets in the one-two grain range in highly mineralized soil. To detect the extremely small nuggets, I found I had to sweep the searchcoil over the ground very slowly, with the coil very close to the surface. My initial testing was done with the detector selected to the normal mode.

I found that changing to the difficult mode or rapid and/or sloppy sweep techniques would result in missing the smallest nuggets but would make any dramatic mineralization changes less of a problem. The important thing I realized while testing the Eldorado MKII is that if this detector can indicate really small nuggets, larger ones would be no problem if care is used in techniques.

Testing larger metal objects, both nuggets and coins, verified this condition. Targets about coin size were tested to depths of up to about eight inches and all gave respectable positive indications. I was impressed with how well the Eldorado MKII detected an eight-inch deep nickel, matching the sensitivity of other more expensive detectors. Another large target (a two-inch square piece of lead I have buried at a depth of about one foot) also responded with a very respectable signal.

The hot rocks also gave responses, one a negative response with no recovery "boing" and a positive response to the other rock. Both of the initial signals caused by the rocks were what I expected; however, I was pleased by the lack of the "overshoot" or "boing" recovery signal normally associated with the negative responding rock.

While testing at home, I noticed a minor but potentially irritating problem. When using high impedance earphones like the Koss models I normally use, I found I could hear a weak but perceptible high-pitch squeal. Later, I tested another MKII and found the squeal to be present also, indicating it is a common condition. Consulting with Wilma Beaumont about the condition, she said that 8- to 32-ohm earphones are recommended for the detector. I found that the use of lower impedance earphones did almost eliminate the noise.

Further evaluating the very faint squeal condition indicated that only a small percentage of people, those with acute sensitivity to high-pitch sounds, could hear the noise.

Arizona Nugget Country

Rich Hill is located just a few miles from Yarnell, Arizona. Those familiar with this area know that some of the best nugget hunting is in areas that are rocky, steep, and have some of the strangest and fastest changing ground conditions.

At the site, I elected to tackle the area using the normal mode of sensitivity. Hunting in this mode gave the greatest response from buried metal objects but also gave distinctive signals to any dramatic mineralization changes. Sudden changes caused by some of the more responsive hot rocks could also be heard. These conditions are common to all sensitive gold-hunting detectors.

I would recommend a beginning nugget hunter start out using the difficult mode of operations until he or she gets the feel of the instrument when hunting in such adverse ground conditions. The slight sensitivity loss is more than compensated by the reduction in false signals caused by the wild soil changes.

Hunting some of the more precarious locations on Rich Hill displayed the obvious need for a couple of options available for the Minelab. One option severely needed was the hip-mount conversion. Although the Eldorado MKII wasn't extremely heavy, use of the detector using recommended mounting of the control unit became very fatiguing. Under awkward conditions, such as uneven ground terrain or trying to scan the side of a hill, it almost became a two hand operation.

In fact, I did see one other nugget hunter using an Eldorado MKII doing just that, scanning a dirt bank while holding the detector stem about halfway down the shaft to shift the weight.

Fortunately, another nugget hunter, Dan Thacker, of Stanton, Arizona, mentioned a trick employed by other Minelab owners. Some people were moving the control unit, from the conventional location Oust in front of the hand grip) to the shaft under the forearm. This mounting procedure really made a difference in the balance and handling of the detector. The control unit seemed to counterbalance the coil weight, making the detector very comfortable when searching precarious locations.

Checking with other Minelab owners in the area indicated mounting the control unit under the forearm was a common practice. Because the detector housing just snaps on the shaft, some people were wrapping the detector and shaft with self-adhesive elastic bandage material. This provided protection from accidental falling of the control unit and added protection for the detector housing when setting it on the ground.

Another option I would like to have had was the optional six-inch coil. When trying to search around and between rocks, I found the manipulation of the eight-inch coil difficult. The standard-size coil, however, excelled in the areas where the ground was fairly level.

Tackling Really Bad Ground

Some of the favorite places to search on Rich Hill involve scanning recently graded areas. One of the difficulties of this type of searching is that the wildly different types of ground conditions become apparent. One of the most severe conditions was streaks of red clay running alongside a greenish clay. The differences in mineralization between them was tremendous.

When passing the searchcoil across the junctions of the two different clays, I could hear a weak but distinctive response similar to a deep target.

This problem haunted all the sensitive detectors in the area. A little trick I employed to determine if the response was caused by the soil was to re-scan the particular area with the searchcoil sweep in line with the streaks rather than across them.

By changing direction of my sweep pattern, I could easily determine that the quickly changing ground conditions were causing the signal response.

Another problem encountered when searching graded areas involved the ever-present metal shavings that had sheared off the grader blade used while the area was graded and from non-ferrous objects.

While searching the graded areas, I found that I couldn't differentiate the small pieces of steel from any nonferrous target, making digging all targets a necessity.

Unfortunately, I didn't find any nuggets during my testing o f the Eldorado MKII but the various sizes of lead and other non-ferrous items I found indicated that I could have easily detected gold if I would have been fortunate enough to pass over it. I knew the problem wasn't the detector's lack of sensitivity but rather luck-mine. One factor that impressed me during my testing in Arizona was the size of some of the lead shavings I found during the testing. They were so small that it took several minutes of careful searching to locate them.


According to Wilma Beaumont, the sensitivity and overall performance of Eldorado MKII is "one of the best kept secrets" of any of the gold-hunting detectors on the market. After trying this detector, I have to agree with her. The detector is not only very sensitive but very stable.

Priced at $395, the Eldorado MKII is a solid, sensitive nugget hunting detector capable of finding both extremely small nuggets and extremely deep ones. Although it lacks the discrimination feature, this new Minelab would be right at home finding deep relics as well as nuggets.

To enhance the versatility of the Eldorado MKII Minelab has several options available including: 6 inch and 14-inch round coils and a 12-inch elliptical.

An optional extension cable and carrying case for hip or body mounting are also available (recommended for extensive nugget hunting in uneven terrain).

For more information concerning the Eldorado MKII contact Down Under Treasures, P. 0. Box 91538, Henderson, NV 89009 or phone (702)565-1353 and tell them you read about it in Lost Treasure.

Author's note: Special thanks to Jim Martin and Big Jim McClennan Of Lost Texan Trading Company, owners of the famous ""Potato Patch" located on Rich Hill, for access to the area to use as a backdrop for some of the pictures.

Reginald G. Sniff s favorite form of TH'ing is gold nugget hunting

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