Promotional Maneuvering and a Final Test
Unavoidably, recreational mining reinforced the ongoing argument of geologists and other advocates of retesting, for the impressive number of finds seemed to indicate that previous tests had, indeed, lost perhaps 50% of the diamonds in their overall samplings.
“With tourists only scratching at the worked and reworked surface, the annual recovery is approximately three times as much at the [Johnston’s] Arkansas Diamond Mine per year as the yield of the massive Martin machinery and all of its mechanized equipment,” said one writer in 1966, echoing a central theme of promotional groups throughout the campaign of the late 1900s.
Speculation about the value of the Crater also continued. In later 1974, for instance, the chief editor of the National Jeweler suggested Arkansas might have acted too hastily in setting the diamond field aside as a public park. “Is it possible Murfreesboro might have become a rich diamond mine if mining companies went deep enough for real pay dirt?” he asked. In 1981, as commercial pressure built, a mining consultant in Little Rock, William P. Rogers, reported that estimates of mining potential were running as high as $5,000,000,000.
The rising interest in Arkansas diamonds sprang basically from a continuing domestic demand for both jewelry and industrial abrasives, but geologists and other diamond hunters drew essential encouragement from long-awaited breakthroughs elsewhere. In the 1970s and early ‘80s, an unprecedented wave of exploration swept through North America and other parts of the world, leading to the discovery of diamond-bearing kimberlites along the Colorado-Wyoming border (first in 1975) and of a different type of diamond-bearing pipe in Australia in late 1979. Although the cluster of kimberlites in Colorado-Wyoming yielded large quantities of tiny diamonds, the deposits were deemed noncommercial. The Argyle Mine in Australia proved highly profitable, particularly as a source of industrial diamonds.
The Argyle pipe’s geological features set it apart from the classic South-African model. Instead of the typical carrot shape, it had a much shallower champagne-glass form. In place of kimberlite, it held olivine “lamproite,” volcanic material of noticeably different mineral composition. And it was located not within the older core of a continent, as in Africa and on the Colorado-Wyoming border, but along the edge of it—as were the deposits in Pike County. Inspired by the Australian model, some geologists decided Arkansas’ deposits were closer to lamproite than to kimberlite, a fine distinction earlier geologists such as Hugh Miser were reluctant to make. The reclassification was accepted generally by 1985.
An organized campaign to open the state park to commercial testing began in the late 1970s and early ‘80s as major companies moved into Pike County and lobbied both local and state officials for permission. Blocked by the state Parks, Recreation and Travel Commission, Cominco, Amselco, Superior Oil, and a few other groups probed the countryside, particularly the known deposits near the Crater. Before 1985 all concluded that if commercial potential existed in southwest Arkansas, it had to be at the Crater of Diamonds.
An all-out campaign for retesting began in the summer of 1985, led by previously unknown promoters based in the Dallas, Texas, area. Their new Arkansas Diamond Development Company of Arkansas was joined by several other newcomers to the field, and within two years the state legislature and the Governor had approved commercial testing and mining in Crater of Diamonds State Park. Promises of great wealth, jobs, and enhanced tourism proved irresistible to those responsible for public policy in Arkansas.
A joint State-private venture financed by interested companies eventually ran two phases of testing, first using long-hole drilling to determine the shape and volume of the Crater (shallow “martini glass” rather than carrot) and then large pits to sample different sections of the pipe. The State’s mining consultant theorized the pipe should average about 20 carats per 100 metric tons.
The final results in 1997, however, were consistent with previous tests. The overall sampling averaged 0.57 carat per 100 metric tons. The historically defined diamond field on the east side of the pipe averaged about 1 carat per 100. On the west side, only a pit by the wide central drain yielded a diamond, and the origin was questionable.
Concluding the affair, the Arkansas State Parks, Recreation and Travel Commission voted to impose a twenty-year ban on further applications for commercial testing at the park. The step was timely because soon after the Phase 2 results were in, history repeated itself—some critics began challenging the test as faulty, inadequate for determining the true value of the Crater. For final resolution, the state legislature followed with its own ban on such commercial activity, essentially restoring the restrictions existing before the legislature and governor approved commercial testing and mining in 1987.
 Leiper, “Celebrating the 69th Anniversary of America’s Only Diamond-Bearing Peridotite Pipe,” 718. The argument had two components: recreational hunters, principally diggers, were recovering diamonds from old “tailings”; otherwise, visitors were continuously reworking the same material (the soil plowed and re-plowed by the State), and therefore the diamonds below were “being wasted.” A bit of historical research and an hour or so of field observation would have qualified the first assertion; awareness of the prominent erosion of the field during rains should have discredited the second.
These themes appeared constantly in reports, statements to the news media, public hearings, and general literature until the final retesting of the Crater in the ’90s. The Crater archive and the author’s files hold ample documentation.
 Cited in Los Angeles Times, Part I, November 10, 1974, p. 3, clipping in IV.H.
 Arkansas Gazette, June 14, 1981, p. 9A. Rogers was president of International Development Consultants, a group active in coal mining, and had served since 1967 as the State’s industrial liaison. He recommended a State task force to study the feasibility of diamond mining at the park—a suggestion carried out later.
 For details, Google “Argyle Mine” and “Diamonds +Colorado-Wyoming. For a firsthand account of the Argyle discovery: http://members.iinet.net.au/~boxer/argyle.html. In 1987, the State Line district of Colorado-Wyoming produced a more promising deposit, the Kelsey Lake Prospect, which eventually became North America’s first commercial producer, in 1996 (Google “Kelsey Lake Diamond Mine”; for a brief introduction, http://www.mineralsocal.org/bulletin/2002/2002_oct.htm).
Finally, persistence also paid off in the wilderness of Canada’s Northwest Territory, with the discovery of vastly richer commercial kimberlites. The sensational Ekati Diamond Mine opened officially in October 1998. Others followed.
 Supra. “Background of Discovery.” Miser and Ross found the peridotite of the Arkansas diamond field “strikingly similar“ to South Africa’s “porphyritic mica peridotite of lamprophyric habitat” (“Diamond-Bearing Peridotite in Pike County, Arkansas,” Economic Geology, 672).
 By that date, any discussion of the Arkansas diamond fields applied lamproite instead of kimberlite. An excellent introduction to the general topic: Michael A. Waldman, Hugo T. Dummett, and Tom McCandless, “Geology and Petrology of the Twin Knobs #1 Lamproite, Pike County, Arkansas,” unpublished report , copy in author’s files. The report included an excellent selective bibliography covering the general trend in Pike County (12-14).
 Exploration outside the park can be traced through the Oil & Gas (Mineral) leases, listed in the basic Deeds index of counties involved. The leading groups were Amselco Exploration Ventures, Cominco American, Superior Oil, Anaconda Copper Company (and Anaconda-ASAM joint venture), and Superior Minerals of Arkansas. A. S. Magness was also active. The Mining Corporation of Arkansas, based in Hot Springs, was involved in leasing land. In the mid ‘80s, LAC Minerals (U.S.A.), Inc., of Fort Collins, Colorado, assumed a leading role–its representative in Arkansas, geologist Mike Waldman, had worked with other groups earlier (see especially, Waldman, et al., “Geology and Petrology of the Twin Knobs #1 Lamproite, Pike County” ).
In the ‘80s and ‘90s, two new companies retested lamproite deposits in the hills, using a new on-site pilot plant and state-of-the-art equipment to assure accuracy. Both the Arkansas Diamond Development Company and Texas Star Resources got virtually the same results as predecessors.
The author’s files and Parks and Tourism’s vertical file (“Crater of Diamonds”) include company proposals to the State, along with reports, news clippings, and other related material. The Arkansas Gazette and Arkansas Democrat covered activities thoroughly, while the Murfreesboro Diamond added considerable detail (the collection of clippings in the Crater archive is helpful, especially for the period before April 1984 [IV.H; also IV.E.5]). For an example of the state Parks, Recreation and Travel Commission’s rigid opposition in the early ‘80s to commercial testing or mining in the Crater, see the Arkansas Gazette, April 17, 1981, A1-2. The decisive pressure for approval came from the state legislature and the governor’s office.
 The Department of Parks and Tourism’s files are comprehensive (“Crater of Diamonds,” vertical); the Crater archive holds selected material, including an excellent file of clippings from various publications. The author’s files cover the promotional campaign organized by various mining interests in the 1980s and ‘90s, including their interaction with State and Federal agencies.
 Ibid. The recurring statement in official proposals was based on John Fuller’s reports, taken out of context and interpreted erroneously. For example, see Arkansas State Parks, Recreation and Travel Commission, “Crater of Diamonds State Park, Temporary Non-Conforming Use Application for Bulk Sampling and Testing” (Little Rock, October 16, 1995), 14, 21, 25, 37, 57. Page 37, “Grade,” said: “Based on knowledge of other lamproite and kimberlite deposits at various locations around the world, it is possible to calculate a range of potential grades. The low estimate of the grade is 15 carats per 100 tonnes (as per the adjusted Fuller data discussed in Section 2.3). The high estimate is 50 carats per 100 tons.” Page 14: “The hypothetical analysis assumes the grade of the pyroclastic units to be 20 carats / 100 tonnes with no diamond content assumed for the magmatic unit [on the west side].” Page 57: “. . . using a realistic grade estimate of 15 carats per 100 tonnes . . ..”
 The State first released test results piecemeal as material from a few pits was evaluated (“Crater of Diamonds State Park Evaluation Program—Weekly Progress Reports by John Morgan,” September 13, 1996-February 8, 1997, Parks and Tourism file and Crater archive [blue binder]). Beginning November 6, 1996, four press releases summarized the ongoing results (ibid.). Then the State issued a 108-page report: “Project Manager’s Report for Phase II Evaluation Program, Crater of Diamonds State Park,” unpublished, Arkansas Department of Parks and Tourism, 1997 (also styled as Morgan Worldwide Mining Consultants, “Crater of Diamonds State Park Evaluation Program, Final Report,” unpublished, Arkansas State Parks, Recreation and Travel Commission, 1997).
After the stunning results of Phase II testing, the Project Manager, John Morgan, finally acknowledged the central role of the original surface concentrate (“Report on crater: Most gems at surface,” Arkansas Democrat-Gazette, 20 Oct 1997, 1D, 4D). Morgan estimated the original pipe had eroded from a level at least as high as West Hill–which rises about eighty feet above most of the diamond field and about 90 feet higher than the southeast corner.
 The supervisor/mineralogist of the Arkansas Geological Commission, Mike Howard, was an outspoken critic: J. Michael Howard, “Summary of the 1990’s Exploration and Testing of the Prairie Creek Diamond-Bearing Lamproite Complex, Pike County, Arkansas,” in J. M. Howard, ed., Contributions to the Geology of Arkansas, 4, Misc. Pub. 18-D (Little Rock: Arkansas Geological Commission, 2000), 63-65.