Geologic Map of the Little Horn Mountains 30′ X 60′ Quadrangle, West-Central Arizona

The Arizona Geological Survey has just released an updated version of the Little Horn Mountains geology. This area is west of Phoenix and borders the Kofa National Wildlife Refuge.

From the author’s description, “This compilation geologic map is a new product that builds upon several past compilations of the same area (Demsey, 1990; Spencer, 1995, Korroch et al., 1997) and contains significant updates across the map area. Some elements from each prior compilation were incorporated, some were refined, and other elements were replaced with new 1:100,000-scale geologic mapping. The bedrock geology has only been minimally changed from that of Spencer (1995), with critical changes coming from new mapping of areas such as Cemetery Ridge and the incorporation of new U-Pb zircon geochronologic results to better constrain unit ages. The surficial geology has been significantly modified from reconnaissance 1:100,000-scale geologic mapping using relatively generalized surficial units.”

See the map and report here:

Grijalva’s Clean Energy Minerals Reform Act Is the Wrong Solution for American Mining

The following article is written by Congressman Pete Stauber who represents Minnesota’s Eighth Congressional District and serves as the ranking member of the Energy and Mineral Resources Subcommittee. Raul Grijalva is chairman of the committee.

Everything in this world is either grown or mined, and if we don’t grow it or mine it in America, we import it. Events from the past few years, namely the COVID-19 pandemic and the Russian invasion of Ukraine, have highlighted America’s hunger for metals, including copper, nickel, cobalt, platinum-group elements, and more. Therefore, Congress needs to boost domestic production. Instead, the majority is putting up more arbitrary hurdles, like the so-called Clean Energy Minerals Reform Act.

Don’t let the name fool you. This legislation, introduced by Chairman Grijalva (D-AZ) and being considered before the House Natural Resources Subcommittee on Energy and Mineral Resources this week, will make it even harder to access clean energy minerals domestically while furthering our reliance on Russia, China, and the Congo. The bill contains several provisions that contribute to longtime goals of the Left: dissuade investment in mining and choke projects to death with an unpredictable permitting process.

Talk to any miner, member of the building trades, or industry expert and you’ll hear the same frustration about mining in America: permitting timelines are too long, too uncertain, and incentivize lawsuits and trial lawyers. Take, for example, the PolyMet project in my northern Minnesota District which is approaching two decades of permitting and litigation. PolyMet proposes to mine copper, nickel, cobalt, and more. It has won every lawsuit thrown its way but is still being targeted by the Biden Administration. We cannot wait 20 years to get the nickel we need; not while state-owned Russian companies are dominating the market.

So, how does the Grijalva bill address our permitting timelines? By adding two more duplicative permit requirements. Adding these permits wouldn’t add just months or years, they could add decades to review. Every permit approval will be met with a lawsuit brought on by an activist group and met with a wink and a nod from a faceless bureaucrat in the Administration, dragging it out further and further. So, instead of PolyMet taking a mere 20 years, it’s a good possibility it could be 40 or 50 years under this Leftist dream.

The Grijalva bill also puts hardrock mining squarely in the crosshairs by upending the claims system. Hardrock mineral rights are established through mining claims. Companies then drill thousands of exploratory holes to determine if the resource is even economical to develop. Only about 1 in every 1,000 discoveries results in a mine. For example, the Twin Metals project in my district has already invested just shy of $1 billion in a new mine, before even starting the permitting process. The bill considered this week would make it an oil and gas-style leasing system, treating copper like you would natural gas, making it even less economical for companies to invest in American resources.

And finally, the bill imposes punitive royalties on hardrock mines in America. Every new mine that survives litigation would be subject to a 12.5% royalty. Meanwhile, existing mines aren’t immune either: a functioning mine would owe 8% of everything they extract to the federal government. Hardrock resources cover a wide variety of minerals, occur in unique geologic formations, and all have varying commodity prices. The one-size-fits-all royalty scheme proposed by Chairman Grijalva and President Biden in his Interagency Working Group Recommendations, like upending the claims system, is another bold attempt to shutter investment.

It makes no sense to subject such a wide variety of minerals to the same, inelastic royalty. For example, lithium in Nevada is derived from a salt brine, while copper and nickel in northern Minnesota will be pulled out of the ground as a solid ore. Meanwhile, mining in Minnesota funds every single school district in the state. If we slap the Grijalva Tax on mines in America, it’ll push companies looking to invest in Minnesota overseas.

America is facing a metals crisis. We can no longer rely on our foreign adversaries to supply us with the copper, nickel, cobalt, and other minerals we need for modern life. Instead of making it harder to mine American resources, as the Grijalva legislation does, there are steps Congress can take to make America an attractive place for mining.

First, we need to update the permitting process. It should not take 20 years to develop our natural resources. Reviews should be timely, transparent, and reasonable. We also need to limit the President’s authority to arbitrarily kill projects with the stroke of a pen. Just this past February, Biden chose to cancel the federal leases held by the Twin Metals project that date back to the 1960’s. Legislation I introduced, the Accessing America’s Critical Minerals Act and the Saving America’s Mines Act, would update our permitting process and end the President’s authority to kill mining with the stroke of a pen.

This week, as Congress considers the so-called Clean Energy Minerals Reform Act, don’t buy the rhetoric. Democrats proposed this legislation to make permitting more difficult and dissuade investment, making our supply chains even more crippled. Let’s instead consider serious proposals that grow mining in America and secure our domestic supply chains. (Source)


I live in Grijalva’s district in Tucson, AZ, and know that he has long been an opponent of mining. Here are some of my posts on his actions:

Grijalva’s Proposed Change to Mining Law Would Be Disastrous for America

Mr. Grijalva, why imposing royalties on hard rock mining is a bad idea

Grijalva’s anti-jobs bills

See also: Mining and the bureaucracy

Economic Impact of Arizona Mining 2021

From the Arizona Mining Association and the Arizona Rock Products Association:

Arizona ranked first among all states for non-fuel mineral resource production in 2021, with output valued at $10 billion. Arizona production in order of value includes copper, sand and gravel, molybdenum, cement, and crushed stone making up the top 5.

Arizona’s direct mining output was $8.0 billion, with mining industry employment of 13,645 and payrolls of $1.5 billion. Arizona copper accounts for 74 percent of U.S. production.

The rock products industry direct output was $2.9 billion, with employment of 8,116 and payrolls of $570 million. Each rock products worker supports 21 Arizona construction jobs.

Including all indirect and induced (secondary) effects, the total economic impact of Arizona’s combined mining and rock products activity was output of $20.0 billion, creating 74,740 total Arizona jobs in the general economy and income of $5.3 billion.

Total state and local Arizona tax revenues associated with mining and rock products activity summed to $772.2 million. Federal taxes due to mining in Arizona were $967.0 million.

Read full 16-page report here.

The Rise and Fall of Hunga Tonga-Hunga Ha‘apai

The Arizona Geological Survey links to a “story book” about the recent volcanic eruption in the southern Pacific Ocean. See the “story book” here.

For more than a decade, a submarine volcano had been erupting in the South Pacific Kingdom of Tonga. In 2015, the volcanic activity united two islands as one, and we witnessed the birth of Hunga Tonga-Hunga Ha‘apai. However, in 2022, the eruptions culminated in the violent self destruction of this volcanic island.”

The eruption on January 15, 2022 released hundreds of times the equivalent mechanical energy of the Hiroshima nuclear explosion. Material was launched as high as 40 kilometers (25 miles) into the stratosphere, blanketing nearby islands with ash and triggering tsunami waves. Hours after the event, the sound from the blast was heard as far away as Alaska, United States.”

Hunga Tonga

Geology and History of the Globe-Miami Mining Region

The Arizona Geological Survey has just published a new paper by David Briggs:

Geology and History of the Globe-Miami Mining Region

Copper mining in the Globe-Miami Mining Region of Arizona’s Copper Triangle spans more than 150 years. In the Arizona Territory, the Globe-Miami Mining Region evolved from a small, insignificant silver camp into one of America’s largest copper producers. The first reported copper production in Globe-Miami Mining Region occurred at the Hoosier mine in 1878 only nine years after silver was discovered. Globe-Miami’s largest early copper producer, the Old Dominion mine, commenced operations during the spring of 1882. Prior to 1911, most of the copper production was derived from high-grade copper veins located in the southern portion of the Globe Hills. During these early years, the major challenges to the development of the area’s vast copper resources were related to its location in a remote mountainous region that made access to eastern markets difficult. High shipping costs to a distant railhead by wagon limited production to only the highest grade ores, making these early operations marginally profitable and vulnerable to minor fluctuations in the price of copper. These impediments were largely resolved with the arrival of the Gila Valley, Globe and Northern Railroad at Globe in December 1898.

Paper citation: Geology and History of the Globe-Miami Mining Region, Gila and Pinal Counties, Arizona. Arizona Geological Survey Contributed Report CR-22-B, 243 p.

Link to full paper:

Other papers by David Briggs:

Helvetia-Rosemont Arizona’s Hardscrabble Mining Camp

History of the Christmas Mine, Gila County, AZ

History of the Ajo Mining District, Pima County, Arizona 

History of the Warren (Bisbee) Mining District

History of the San Manuel-Kalamazoo Mine, Pinal County, Arizona

Recovery of Copper by Solution Mining Techniques

Superior, Arizona – An Old Mining Camp with Many Lives

History of the Copper Mountain (Morenci) Mining District

History of Helvetia-Rosemont Mining District, Pima County, Arizona

History of the Silver bell mining district

The men, mines, and geology of the Verde Mining District, Jerome, Arizona

Telling time at Grand Canyon National Park

This work by the National Park Service summarizes the geochronology and shares insights on the geology of rock units exposed in Grand Canyon. The 54 page report contains 35 figures and 10 tables.
Executive Summary
Grand Canyon National Park is all about time and timescales. Time is the currency of our daily life, of history, and of biological evolution. Grand Canyon’s beauty has inspired explorers, artists, and poets. Behind it all, Grand Canyon’s geology and sense of timelessness are among its most prominent and important resources.
Grand Canyon has an exceptionally complete and well-exposed rock record of Earth’s history. It is an ideal place to gain a sense of geologic (or deep) time. A visit to the South or North rims, a hike into the canyon of any length, or a trip through the 277-mile (446-km) length of Grand Canyon are awe-inspiring experiences for many reasons, and they often motivate us to look deeper to understand how our human timescales of hundreds and thousands of years overlap with Earth’s many timescales reaching back millions and billions of years.
This report summarizes how geologists tell time at Grand Canyon, and the resultant “best” numeric ages for the canyon’s strata based on recent scientific research. By best, we mean the most accurate and precise ages available, given the dating techniques used, geologic constraints, the availability of datable material, and the fossil record of Grand Canyon rock units. This paper updates a previously-published compilation of best numeric ages (Mathis and Bowman 2005a; 2005b; 2007) to incorporate recent revisions in the canyon’s stratigraphic nomenclature and additional numeric age determinations published in the scientific literature.
From bottom to top, Grand Canyon’s rocks can be ordered into three “sets” (or primary packages), each with an overarching story. The Vishnu Basement Rocks were once tens of miles deep as North America’s crust formed via collisions of volcanic island chains with the pre-existing continent between 1,840 and 1,375 million years ago. The Grand Canyon Supergroup contains evidence for early single-celled life and represents basins that record the assembly and breakup of an early supercontinent between 729 and 1,255 million years ago. The Layered Paleozoic Rocks encode stories, layer by layer, of dramatic geologic changes and the evolution of animal life during the Paleozoic Era (period of ancient life) between 270 and 530 million years ago.
In addition to characterizing the ages and geology of the three sets of rocks, we provide numeric ages for all the groups and formations within each set. Nine tables list the best ages along with information on each unit’s tectonic or depositional environment, and specific information explaining why revisions were made to previously published numeric ages. Photographs, line drawings, and diagrams of the different rock formations are included, as well as an extensive glossary of geologic terms to help define important scientific concepts.
The three sets of rocks are separated by rock contacts called unconformities formed during long periods of erosion. This report unravels the Great Unconformity, named by John Wesley Powell 150 years ago, and shows that it is made up of several distinct erosion surfaces. The Great Nonconformity is between the Vishnu Basement Rocks and the Grand Canyon Supergroup. The Great Angular Unconformity is between the Grand Canyon Supergroup and the Layered Paleozoic Rocks. Powell’s term, the Great Unconformity, is used for contacts where the Vishnu Basement Rocks are directly overlain by the Layered Paleozoic Rocks. The time missing at these and other unconformities within the sets is also summarized in this paper—a topic that can be as interesting as the time recorded.
Our goal is to provide a single up-to-date reference that summarizes the main facets of when the rocks exposed in the canyon’s walls were formed and their geologic history. This authoritative and readable summary of the age of Grand Canyon rocks will hopefully be helpful to National Park Service staff including resource managers and park interpreters at many levels of geologic understanding; the glossary helps explain geoscience terms and the references cited section provides up-to-date peer reviewed resources for deeper inquiry

Recent seismic excitement in the area of the 1887 Great Sonoran Earthquake

From the Arizona Geological Survey:

On July 31, 2021, a magnitude (M) 5.2 earthquake occurred in northeastern Sonora, in the area where the Great Sonoran earthquake occurred in 1887. This earthquake is the largest in that area for many decades, probably for more than 100 years. In addition, several M3-3.5 earthquakes occurred in the following weeks 100 km to the north in the bootheel of New Mexico. (read more)

See also: The Great Arizona-Sonora Earthquake of 1887

The past, present, and future state of Tucson’s creeks and rivers

From the Arizona Geological Survey:

‘The past, present, and future state of Tucson’s creeks and rivers’, a #StoryMap by the Watershed Management Group (a 501 (c) non-profit). The presentation includes some excellent historic images, diagrams, and interactive maps showing flow conditions, past and present, in Tucson drainages. Most illustrations have explanatory text. Just scroll down through the article.

Take a look.