Geology topics

Andrew L. Gulley

Publications and source records attributed to Andrew L. Gulley.

8 recordsLinked to original sources

USGS2026

Indirect mineral import reliance and provenance

Mineral commodity supply chain analyses rely on international trade data reported by individual countries as quantities of a mineral commodity form imported from (or exported to) a partner. However, export quantities frequently exceed a country’s domestic production, or occur when no production data are reported, suggesting that the trade partner is merely an intermediary in a transshipment. These discrepancies can result in misleading conclusions regarding supply chain vulnerabilities and dependencies. We present a two-stage methodology to reconcile gaps between reported material sources and actual producers. First, we construct trade networks for specific mineral forms, treating production as a type of import to distinguish producing nations from entrepôts. By tracing flows through these networks, we attribute a target country’s imports to original producers via both direct (in a single trade link) and indirect (transferring through intermediaries) pathways. Second, these production-attributed flows are incorporated into multi-stage supply chains to determine the upstream provenance of feedstock for domestic refining and processing. This approach provides a more representative picture of trade reliance. For example, while the United States (U.S.) Geological Survey reports no imports of unwrought antimony metal from Russia in 2022 (U.S. Geological Survey (2025). Mineral Commodity Summaries 2025. 10.3133/mcs2025), our analysis reveals that over 16% of U.S. imports can be traced back to Russian mining through intermediate processing in countries such as China, India, and Vietnam. Additionally, our analysis of the aluminum supply chain shows that while the U.S. is reported as 52% net import reliant on aluminum materials in 2022, it is 100% reliant on foreign bauxite, 7% of which arrived indirectly. This unreported reliance, which is predominantly tied to bauxite mined in Brazil (43%) and Jamaica (28%), highlights our methods ability to capture the supply chain’s dependence on foreign feedstock that may be missing in single-stage trade data.

Mineral Economics↗

USGS2025

World minerals outlook—Cobalt, gallium, helium, lithium, magnesium, palladium, platinum, and titanium through 2029

Given the rapid expansion in the demand for mineral commodities that underpin worldwide economic growth and technological advancement, information regarding expected country-level mine production and production capacity is becoming increasingly important to industry stakeholders, end users, and policymakers. Production capacity can limit future supply, depending on how rapidly that capacity is able to expand. Current capacity can be evaluated on the basis of past production. Decreases to future capacity can be taken into account from announcements of planned shutdowns of mines or processing facilities, which are frequently publicized well in advance of such closures. Likewise, capacity expansions, which usually involve multiple stages—such as permitting, financing, and construction (all of which take time)—can also be estimated. As such, it is possible to evaluate midterm future capacity based on estimates of today’s capacities along with consideration of future investment plans. This World Minerals Outlook provides estimated capacities for cobalt, gallium, helium, lithium, magnesium, palladium, platinum, and titanium for 2025 through 2029. The results of this analysis indicate that two mineral commodities important to the manufacture of lithium-ion batteries—cobalt and lithium—are expected to have large capacity growth in the next few years, likely owing to expectations for increased demand for these batteries. For gallium, helium, palladium, and platinum, capacity is expected to remain stable or exhibit moderate growth. Still, these expected capacity levels are higher than current production, allowing for future production growth. The production capacity outlook is opaque for magnesium and titanium metal, which have a significant fraction of current production in nonmarket economies, such as China and Russia. Ultimately, though, where free market conditions prevail, full utilization of capacity potential for those commodities is likely to depend on supply deficits and prices that are above production costs.

Scientific Investigations Report↗

USGS2024

The development of China’s monopoly over cobalt battery materials

While previous resource conflicts have often been linked to fuel minerals such as oil, future resource conflict may revolve around nonfuel minerals that enable strategic emerging technologies. During a 2010 diplomatic dispute, China reportedly blocked exports of rare earth elements to Japan, thereby leveraging China’s near-monopoly to threaten Japanese manufacturers of advanced technologies including batteries and permanent magnets. Although this caused significant concern for manufacturers outside China, China’s control over other critical minerals has yet to be studied comprehensively. Besides rare earth elements, perhaps no mineral has received more attention for its supply risks than cobalt. Here Chinese control is estimated for each cobalt material at each stage of the cobalt supply chain from 2000 through 2022. The results show that from mining, to refining, consumption, recycling, stocks, and trade, China dominates the cobalt materials that feed lithium-ion battery cathode production. Specifically, the results show that in 2022 Chinese firms had control over 62% of cobalt mine materials primarily used for cobalt chemical refining, 95% control of refined commercial-grade cobalt chemicals, 92% control of battery-grade tricobalt tetroxide, 85% control of battery-grade cobalt sulfate, and 91% control of nickel–cobalt-manganese cathode precursor materials. China’s monopoly over cobalt battery materials may imply a serious supply risk to non-Chinese battery producing and consuming industries—especially given rising geopolitical tensions and the reemergence of critical mineral export restrictions including gallium for semiconductors, germanium for solar panels, graphite for lithium-ion batteries, and (again) rare earth elements.

Mineral Economics↗

USGS2023

China, the Democratic Republic of the Congo, and artisanal cobalt mining from 2000 through 2020

From 2000 through 2020, demand for cobalt to manufacture batteries grew 26-fold. Eighty-two percent of this growth occurred in China and China’s cobalt refinery production increased 78-fold. Diminished industrial cobalt mine production in the early-to-mid 2000s led many Chinese companies to purchase ores from artisanal cobalt miners in the Democratic Republic of the Congo (DRC), many of whom have been found to be children. Despite extensive research on artisanal cobalt mining, fundamental questions about its production remain unanswered. This gap is addressed here by estimating artisanal cobalt production, processing, and trade. The results show that, while total DRC cobalt mine production grew from 11,000 metric tons (t) in 2000 to 98,000 t in 2020, artisanal production only grew from 1,000 to 2,000 t in 2000 to 9,000 to 11,000 t in 2020 (with a peak of 17,000 to 21,000 t in 2018). Artisanal production’s share of world and DRC cobalt mine production peaked around 2008 at 18 to 23% and 40 to 53%, respectively, before trending down to 6 to 8% and 9 to 11% in 2020, respectively. Artisanal production was chiefly exported to China or processed within the DRC by Chinese firms. An average of 72 to 79% of artisanal production was processed at facilities within the DRC from 2016 through 2020. As such, these facilities may be potential monitoring points for artisanal production and its downstream consumers. This finding may help to support responsible sourcing initiatives and better address abuses related to artisanal cobalt mining by focusing local efforts at the artisanal processing facilities through which most artisanal cobalt production flows.

PNAS↗

USGS2022

One hundred years of cobalt production in the Democratic Republic of the Congo

Cobalt is an indispensable element for the manufacture of strategic technologies including advanced batteries, jet engines, rare-earth permanent magnets, petroleum catalysts, and tool parts that enable construction, manufacturing, and mining. Cobalt routinely scores high in mineral supply risk assessments due to the concentration of cobalt mine production in the Democratic Republic of the Congo (DRC). This stands in contrast to the fact that DRC cobalt mine production had a 20% compound annual growth rate from 1995 through 2020—in large part due to investments by Chinese firms beginning in the mid-2000s. Given this continuous growth, one may ask why this supply is perceived to be so risky. This analysis illuminates the causes of historic disruptions to DRC cobalt mine and refinery production by analyzing country-level production, historical reports, and cobalt prices back to 1924. The results indicate that the main causes of supply disruptions were damage to transportation routes, underinvestment in maintaining nationalized mining assets, and the disintegration of the DRC economy during the early 1990s. On the other hand, cobalt mine production increased 50% from 1977 to 1979 despite two secessionist conflicts in DRC's cobalt producing region and increased seven-fold from 1996 to 2003 despite two African wars over the DRC and its resources. These results indicate that—barring another economic disintegration or mining industry nationalization—DRC mine production will likely continue to be the dominant supplier of the world's growing demand for cobalt in lithium-ion batteries. These results also indicate that sustained development of transportation (and other) infrastructure in Africa, as well as support for good governance in the DRC may prove key to the continued stability of DRC cobalt mine supplies.

Resources Policy↗

USGS2020

Evaluating the mineral commodity supply risk of the U.S. manufacturing sector

Trade tensions, resource nationalism, and various other factors are increasing concerns regarding the supply reliability of nonfuel mineral commodities. This is especially the case for commodities required for new and emerging technologies ranging from electric vehicles to wind turbines. In this analysis, we utilize a conventional risk-modeling framework to develop and apply a new methodology for assessing the supply risk to the U.S. manufacturing sector. Specifically, supply risk is defined as the confluence of three factors: the likelihood of a foreign supply disruption, the dependency of U.S. manufacturers on foreign supplies, and the ability of U.S. manufacturers to withstand a supply disruption. The methodology is applied to 52 commodities for the decade spanning 2007-2016. The results indicate that a subset of 23 commodities, including cobalt, niobium, rare earth elements, and tungsten, pose the greatest supply risk. Importantly, this supply risk is dynamic, shifting with changes in global market conditions.

Science Advances↗

USGS2019

China’s domestic and foreign influence in the global cobalt supply chain

In addition to increasing interest in the supply risk of minerals produced in China, there is also concern that China’s efforts to mitigate mineral supply risk—through foreign direct investment—may limit mineral availability for other countries in the short-term (due to production capacity constraints). However, little is publicly known about the quantity of global mineral production that is subject to Chinese ownership-influence or how this influence may mitigate China’s import reliance for mineral commodities. In this analysis, we estimate China’s ownership-share of foreign production for cobalt mine and intermediate materials (in the year 2016), as well as the net import reliance of China’s cobalt refinery industry—which is then adjusted to reflect China’s ownership-share of foreign production. First, we find that China’s foreign cobalt ownership is predominantly in the Democratic Republic of the Congo, the largest source of cobalt mine and intermediate imports for China’s growing cobalt refinery industry. Second, foreign direct investment provided China with ownership-influence over roughly 29% of its cobalt mine and intermediate imports in 2016—which may have reduced the exposure of China’s refinery industry to supply risk from a net import reliance of 97% (on cobalt mine and intermediate materials) to an adjusted net import reliance of 68%. Third, China’s global production share jumps from 2% to 14% (for cobalt mine material) and from 11% to 33% (for cobalt intermediate material) when China’s foreign ownership production share is added to China’s domestic production share. Fourth, over time China’s foreign direct investment appears to have targeted facilities with progressively larger cobalt production capacities. Finally, China’s global production share increases as cobalt material moves downstream (i.e. mine, 14%; intermediate, 33%; refined, 50% in 2016). If a primary motivation of China’s Going Out Strategy is to secure natural resources, then China’s global production share may be reserved for Chinese manufacturers. This analysis may, therefore, indicate that critical mineral availability and supply risk (for countries other than China) may not be confined to minerals produced in China.

Resources Policy↗

USGS2018

China, the United States, and competition for resources that enable emerging technologies

Historically, resource conflicts have often centered on fuel minerals (particularly oil). Future resource conflicts may, however, focus more on competition for nonfuel minerals that enable emerging technologies. Whether it is rhenium in jet engines, indium in flat panel displays, or gallium in smart phones, obscure elements empower smarter, smaller, and faster technologies, and nations seek stable supplies of these and other nonfuel minerals for their industries. No nation has all of the resources it needs domestically. International trade may lead to international competition for these resources if supplies are deemed at risk or insufficient to satisfy growing demand, especially for minerals used in technologies important to economic development and national security. Here, we compare the net import reliance of China and the United States to inform mineral resource competition and foreign supply risk. Our analysis indicates that China relies on imports for over half of its consumption for 19 of 42 nonfuel minerals, compared with 24 for the United States—11 of which are common to both. It is for these 11 nonfuel minerals that competition between the United States and China may become the most contentious, especially for those with highly concentrated production that prove irreplaceable in pivotal emerging technologies.

Proceedings of the National Academy of Sciences of↗