The Unseen Foundation of a Modern Mine
Survey control is the invisible foundation of any large construction or mining project. It ensures every design, map and structure is built in the right place and at the right scale. At Red Dog Mine, one of the world’s largest zinc producers, located in a remote and geologically active part of Alaska, this foundation is critical.
Over time, however, Red Dog’s original survey control had become unreliable. The mine’s “Red Dog Mine Grid,” a local coordinate system loosely tied to the North American Datum of 1927 (NAD27), worked well enough when the mine was smaller. But as operations expanded across a wider area, the system became distorted and less accurate. Most of the original survey monuments were eventually destroyed, leaving only one intact and making the system increasingly difficult to rely on.
To address these challenges, R&M developed a new, high-precision geodetic control system built to modern standards. This framework now supports everything from engineering design and drone mapping to heavy equipment operations and long-term monitoring. Given Red Dog’s extreme weather, shifting ground conditions and high safety stakes, accuracy down to fractions of an inch is essential. The result is a robust foundation for safe construction, reliable infrastructure monitoring and efficient project execution.
This article explores a multi-year case study in establishing and verifying the stability of Red Dog’s geodetic coordinate system and monument network. It also shows how a well-planned verification program is central to ensuring long-term stability, safety and operational integrity.
From Legacy Grid to a Modern Standard
The mine’s original survey control network, known as the “Red Dog Mine Grid,” was loosely based on a 1920s system. While that might have worked for small, localized projects, it became unreliable as the mine expanded. For upcoming critical dam construction and monitoring projects, the old grid simply wasn’t good enough.
The solution was to create a new system tied to modern national standards. R&M’s work included:
- Establishing new geodetic benchmarks in stable locations, designed to resist frost heave and mining disturbance.
- Upgrading the GNSS base station to meet National Geodetic Survey (NGS) specifications for a Continuously Operating Reference Station (CORS). This allows continuous monitoring and inclusion in the national network.
- Defining a new coordinate system for mine-wide use, tied to the North American Datum of 1983 (NAD83, 2011 realization).
- Setting a reliable vertical reference using the North American Vertical Datum of 1988 (NAVD88) with the latest GEOID model to translate satellite heights into ground elevations.
This new foundation was completed in fall 2021 and brought Red Dog into alignment with national spatial reference standards, ensuring the accuracy and longevity of its survey system.
AKRD: An Extremely Stable CORS
To anchor the new geodetic framework, R&M worked closely with NGS and Red Dog surveyors to establish a highly stable CORS at the mine. The new base station, designated AKRD, rests on a steel pipe set 25’ into the ground and anchored into 15’ of bedrock with concrete, ensuring long-term physical stability in Alaska’s challenging conditions.
The NGS formally accepted AKRD into the national CORS network in fall 2021, following coordinate adjustments and validation performed that September. With its inclusion, AKRD not only provides a trusted local control point for Red Dog but also fills a 132-kilometer gap in the regional NGS network — a major contribution to Alaska’s geodetic infrastructure.
AKRD continuously records GNSS data and transmits Real-Time Kinematic (RTK) corrections at the mine using dedicated 450 MHz and 900 MHz radio frequencies, as well as internet-based NTRIP broadcasting. These real-time corrections allow Red Dog Mine surveyors to maintain centimeter-level accuracy for all surveying activities related to mine operations, dam construction and monitoring, and other civil projects. The station’s proven reliability provides a stable foundation for all survey operations at Red Dog, ensuring consistent accuracy year after year.
CORS base station photo
Annual Checkups: Verifying Stability
With the modern network established, the focus shifted from creation to maintenance. To keep it reliable, R&M developed an annual verification program. Each year, R&M surveyors return to conduct an annual verification campaign, which includes:
- Equipment Preparation: Before measurements begin, all survey equipment is rigorously inspected. Tripods are checked for damage, locking screws are tightened and tribrachs are calibrated. GNSS receiver batteries are fully charged and data collection settings are reviewed to ensure consistent and accurate results.
- Static GNSS Sessions: At the core of the program are multi-day Global Navigation Satellite System (GNSS) observations. The three main geodetic monuments are measured simultaneously using Trimble R10 receivers for at least five hours each day over three consecutive days. Start times are staggered by four hours or more to capture a variety of satellite configurations. During these sessions, additional secondary monuments across the mine site are also tied into the network using static survey techniques.
- Data Processing: Raw GNSS data is downloaded and reviewed daily in the field office, allowing the team to identify and resolve any issues right away. After fieldwork, the final data is processed with precise satellite orbit information in Trimble Business Center. This step ensures the highest possible accuracy and the software is regularly updated to take advantage of the latest improvements in GNSS processing.
- Network Expansion: The verification effort goes beyond just checking the system. In 2022, for example, new secondary monuments were added to strengthen the framework. Expanding the network ensures backup points are in place if existing markers are lost and it brackets the entire operation, from the tailings storage facility to the Port, so the control system continues to match the mine’s growing footprint.
Proof in the Data
The annual verification program has created a clear, multi-year record of the control network’s performance. Each year, after data is processed and the network is adjusted, the conclusion has been the same: the system is very stable. The year-over-year shifts in the main survey monuments are extremely small, usually just a few hundredths of a foot, providing a solid and reliable foundation for all survey work at the mine.
The table below shows the position changes, or “deltas,” for two of the primary monuments. Each year’s measurements are compared against the baseline positions established in 2021.
Annual Monument Position Deltas (in feet) from 2021 Baseline
| Monument | Year | Delta North | Delta East | Delta Elevation |
| PT #1 (NANCY) | 2022 | -0.0055 | 0.0184 | 0.002 |
| PT #1 (NANCY) | 2023 | -0.0078 | -0.0101 | -0.009 |
| PT #1 (NANCY) | 2024 | 0.0122 | 0.0166 | 0.028 |
| PT #2 (BETSY) | 2022 | -0.0068 | 0.0179 | 0.010 |
| PT #2 (BETSY) | 2023 | -0.0094 | 0.0096 | -0.030 |
| PT #2 (BETSY) | 2024 | 0.0088 | 0.0154 | 0.033 |
These numbers may look small, but that’s the point. Variations of a few hundredths of a foot are well within the expected tolerance for precise surveying and confirm the primary monuments are anchored in stable ground. For context, horizontal shifts have typically been less than two-hundredths of a foot year to year — remarkably consistent for such a challenging environment.
The program also proves its sensitivity to real change when it happens. In 2024, one secondary monument (VAL) was found to have risen by 0.133’ — more than an inch. Mine staff confirmed this shift through their own monthly checks. This outcome demonstrates that the system does exactly what it is designed to do: confirm stability where it exists and flag movement where it occurs.
Proactive Maintenance: Preparing for the Future
Beyond simple verification, the annual program also addresses future challenges. During the 2024 fieldwork, R&M upgraded the Trimble Alloy receiver at the mine’s CORS site with new Ionoguard technology, which protects against GNSS signal interruptions caused by solar storms. This is especially important during the current peak of Solar Cycle 25, when increased solar flares and coronal mass ejections can disrupt satellite-based positioning and can cause issues when using GNSS equipment. By anticipating these issues, the mine’s GPS-based operations remain dependable even under challenging conditions.
The Value of a Long-Term Geodetic Partnership
Red Dog’s journey from an outdated local grid to a modern, stable and actively managed system shows the value of long-term geodetic monitoring. Establishing a control network is only the beginning — maintaining and verifying it year after year through a consistent, disciplined and expert-led verification program is what ensures reliability.
Through this program, the mine now has:
- A geodetic framework tied to national standards.
- Proven stability in its primary monuments.
- A proactive process that adapts to environmental and operational changes.
- Confidence in the accuracy of all dependent engineering and construction projects.
The level of precision and reliability that Red Dog now has is not an accident; it is the direct result of a strong partnership between the mine’s operational team and dedicated survey professionals committed to upholding the highest standards of geodetic practice. The unseen foundation at Red Dog is not just stable, it is verified.
Is your critical infrastructure built on a foundation you can trust? Share your experiences with long-term geodetic monitoring in the comments below or contact R&M Consultants to discuss your project’s needs.
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