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Geomorphology 

 
Author:Jack Caldwell

Summary

This review discusses the principles of geomorphology as applied to mining and reclamation. Links to software, online courses, and a number of papers related to geomorphology from the United States, Australia, and Pakistan are given.

INTRODUCTION

The only rule you need to reclaim your mine site in accordance with the principles of geomorphology is if you don't see it in nature, don't do it.

I am indebted for this wisdom to Nicholas Bugosh of Carlson Software. At the SME meeting in Salt Lake City in 2008, he kindly spent time showing me how his software can be used to incorporate geomorphic perspectives and principles into the design of mine reclamation landscapes and surface water networks. I write more of his software in this review.

By way of further introduction, let me confess an utter fascination with geomorphology as a pure science-I read most anything about it I lay my hands on. I am not an expert, so best refer to the links I provide here for the details and the experts. If you can help me make this a better piece and source of information for the mining industry, I would appreciate your input.

UMTRA BACKGROUND

By way of background, I admit to great sympathy with the geomorphic approach to design of mined land reclamation works. Recently I visited three uranium mill tailings piles in Colorado closed in accordance with the design criterion: stability for 1,000 years to the extent reasonable, and at any rate for 200 years. A long time ago I walked the lands of the southwest with a professional geomorphologist as we sought to characterize the landforms, erosion processes, and changes of topography in the last 10,000 years and tried to apply these observations to the prediction of the next 1,000 years of topographic change. We then formulated the conceptual designs for the 24 piles that constitute the Title I UMTRA Project.

Our ideas and approaches did not gain currency outside the uranium tailings remediation arena because of concern for the costs of the works we designed and constructed. And this is understandable. But the tide seems to have changed: now we see British Columbia write about wrap-around waste piles, and O'Kane engineers promoting natural geomorphic shapes for their clients' mine waste disposal facility closure. And the geomorphic approach has a new and profound application in the Oil Sands-the difference is a move away from the requirement for long-term geomorphic stability to an even more profound application of geomorphic response equilibrium. I quote: "It is preferable to create a mature landscape on mine closure, so that the expected rate of change will be comparable to the reclaimed landscape in geologic time."

SOFTWARE

Nicholas Bugosh of Carlson Software is the creator of Carlson Natural Regrade with GeoFluv. This is described in these glowing terms on their web, but I suspect it is true so I repeat it here:

There is something new happening in landform design. It's the future. It's natural. Be a part of it. Carlson Natural Regrade with GeoFluv™ applies fluvial geomorphic principles to upland landform design. This unique Carlson 2007 module helps you to create a landscape design that mimics the functions of the natural landscape that would naturally evolve over time. The result is a stable hydrologic equilibrium ... naturally.

If fact, the U. S. Department of the Interior's Office of Surface Mining (OSM), Reclamation and Enforcement has identified Carlson Natural Regrade as a 'TIPS Core Software'. See this October 12, 2006 news release for full details.

If you want to see more and learn more, I recommend you do what I did: load and watch the Natural Regrade Webinar, described thus (and I agree again, so I repeat it again.)

This webinar is presented by Nicholas Bugosh, the creator of Natural Regrade, and was originally broadcast on August 31, 2007. In this webinar Nicholas demonstrates Natural Regrade's incredible ability to design surfaces that drain the way nature designed, with minimal erosion. Unique in the industry, Carlson Natural Regrade is an amazing solution to one of the key challenges of site design.

As an aside, Carlson also has software to use with your surface water studies.

EDUMINE

Before you start doing geomorphology at your mine, I would recommend that you know and quantify the surface water of your mine site. On EduMine are three courses I have compiled that may help: Surface Water Management at Mines; Groundwater in Mining; and Mine Water and Chemical Balance Analysis. Also consult the course Surface Reclamation Techniques 1: Topsoil, Hydrology and Topography.

PAPERS RELEVANT TO MINE GEOMORPHOLOGY

NEW HAMPSHIRE GEOMORPHOLOGY
There are no mines in New Hampshire that I know of; except surely some aggregate mines and gravel pits? Regardless, the volume I refer you to does not address the impact of mining at all. But I cannot resist bringing this fine volume to your attention: White Paper, River Restoration and Fluvial Geomorphology published in May 2006 by the New Hampshire Department of Environmental Services Department of Transport. It is worth reading this volume if only for the clear text, fine illustrations, and sound advice re restoration of disturbed fluvial features. I suspect that anyone involved with mine land reclamation and surface way management at a mine would enjoy this one.

LES SAWATSKY AND OIL SAND MINE GEOMORPHOLOGY
InfoMine has twelve technical papers by Les Sawatsky and his many coauthors in the InfoMine Library. You can access them through the Library using the author's name as a keyword or via the author search.

Because of the technical significance of these papers both to reclamation of Oil Sands mines and the greater mining industry, we summarize and survey the papers in this review. The primary focus of the papers and hence of this review is the application of the principles of geomorphology to mined land reclamation.

The basic plea and principles are set out by Sawatsky et al. in the paper Integrated Mine Water Planning and for Environmental Protection and Profitability. In this paper the authors plead for multidisciplinary input, acceptance of environmental and economic goals, partnership amongst planners, designers, operators, and regulators, acceptance of water issues being equal to mining concerns, innovative solutions at an early stage of mine planning, a sound understanding of natural analogues, data collection and monitoring, inventory of baseline fluvial and geomorphic conditions, early establishment of design criteria, and planning by iteration.

These ideas are further explored in the paper by Sawatsky and Beakstead Geomorphic Approach for Design of Sustainable Drainage Systems for Mineland Reclamation. Here the authors point out that uniform landscapes are immature and that rivers meander, balance develops between erosion and sedimentation, and that flood plains attenuate flows. The authors call for application of these obvious geomorphic facts in the design of mined land reclamation works.

In their paper Mine Planning Guidelines for Developing Sustainable Drainage Systems, Sawatsky et al. posit these guidelines:

  • To the extent reasonable, pre-development surface flows to receiving waters should be restored; for example they recommend that the ten-year flow to receiving waters should not exceed the pre-development flow by more than thirty percent.
  • Avoid side-hill diversions that may be blocked by ice, beaver dams, or sediment.
  • End-of-mine lakes should be at the end of flow paths.
  • Liquid impoundments, including final tailings ponds, should be below grade.
  • Final grades should be less than pre-development grades to account for the greater erodabilty of the reclamation soils.
  • Major drainage courses should be on undisturbed ground at low gradients that limit erosion.

The principles are applied as described in the paper Natural Analogs For Sustainable Landscape Design at Syncrude, Keys et al. establish these criteria:

  • Create a geomorphically mature reclamation landscape.
  • Create a robust landscape - one which improves in stability with time.
  • Create a landscape that mimics natural systems in the area.
  • Use Best Available Demonstrated Control Technology.
  • Invoke a design-for-closure philosophy to be implemented in design and operation.

They expand on the application of these principles in practice, including providing information on the geomorphic processes and rates operative in the area of the mine, the design of mine lakes, accommodation of beaver dams, placement of rip-rap to control stream erosion, aeolian erosion of tailing piles 60 m above the natural landscape, and post-mining maintenance and monitoring.

Writing of the application of the principles discussed above to a coal mine in the United States, Beersing et al. in the paper A Geomorphic Approach for the Design of Drainage Systems on Reclaimed Mined Area establish these criteria for replicating natural analogues in the design of reclamation drainage systems:

  • Robust, self-healing capacity provided by several lines of defense against sustained erosion.
  • Ready supply of armoring material where erosion has occurred.
  • Adjustment of channel size and shape to handle peak flows.
  • Gradual evolution.
  • Sediment balance.
  • A stable configuration that is not vulnerable to rapid change.

In an eloquent plea for the adoption of rational sediment yield criteria to mine land reclamation, in the paper A Strategy for Determining Acceptable Sediment Yield for Reclaimed Mine Lands, Bender et al. set out these criteria for a sustainable landscape:

  • Provide terrain suitable for appropriate terrestrial ecosystems.
  • Produce similar runoff characteristics to the natural hydrologic regime of downstream receiving waters.
  • Provide landscape features that are not susceptible to high rates of erosion such as results from gully formation.

On the basis of a detailed examination of the factors that affect the health of receiving waters, the authors conclude that the following guidelines should be used to establish acceptable sediment yields:

  • Avoid significant changes in sediment yield, where a significant change may be quantified as two to ten times background.
  • Limit the risk of high suspended sand concentrations to short durations.
  • Provide equal of better habitat for species spawning, feeding, and overwintering.

Gullies are the main source of eroded soil from a mine or any slope that is steeper than the natural surrounding topography. We have all seen the severely gullied slopes on many a mine waste disposal facility. I have walked the 1,000-year old gullies of the Cahokia Mounds in East St. Louis and the gullies that have been developing for 10,000 on the badlands of the western United States. I have wondered at the deep new gullies that develop in one winter on reclaimed mines in Idaho. Sawatsky and Tuttle write of the factors involved in gulley formation in Occurrence and Growth of Gullies on Mine Disturbed Land. In this fact-filled paper, they note that the primary causes of gulley formation at Syncrude are an absence of vegetation and terrace ponding. They also note self-healing gullies; i.e., those where gravel and/or vegetation accumulate and inhibit continued growth of the gulley.

In many ways these earlier papers by Sawatsky and coauthors are but a run up to the 2004 paper where their developed and more mature ideas are set out. I cannot quote all I would like to from the papers by Sawatsky entitled Reclamation Strategies that Address Mine Closure Drainage. But if you choose to read only one paper, this is the paper I recommend. Here are some quotes that caught my attention:

  • "Unlike natural landforms that have been subjected to 1,000s of years of natural erosion and sedimentation, constructed landforms are vulnerable to relatively high rates of erosion if the topography is not contoured to suit shapes that represent a dynamic equilibrium in natural systems."
  • "Mine disturbed land is composed of steeper terrain, reduced topographic complexity, and thin cover layers of organic soil relative to pre-development conditions. Without mitigation such features result in higher flood peaks, reduced low flows, and reduced water retention to support vegetation. This might result in increased erosion, reduced vegetation productivity, and inferior aquatic habitat."
  • "A common misunderstanding is that terraces prevent erosion. Although terraces intercept runoff during low intensity storms, erosion can only be controlled if the accumulation of surface water does no exceed the storage capacity on the terrace or if the resulting spillage is properly controlled by a spillway structure."

This paper is full of many checklist, practical design advice, case history wisdom, and reality-base advice. I recommend it if your business in mined land reclamation.

Here are the other four papers by Sawatsky that I do not review-not because they are not good (if you can follow the multiple negatives) but because they are not apposite to the topic of this piece. Nevertheless, I recommend you access them and read them:

CALIFORNIA
Channel Geomorphology Assessment: A Component of the Sulphur Creek Watershed, Napa County, California published in 2003 by the Napa County Resource Conservation District is a fine example of the detail required to quantify the geomorphological characteristics of a single waterway, and to establish the basis for intelligent action that might impact the geomorphology of the waterway, including any mining activity. In this case gravel mining had been undertaken for almost 100 year prior to 1999. The report concludes that the gravel mining probably had not significantly impacted pre-existing conditions, except for increasing the flood capacity of the mined reach. Now that there is no mining, the channel is silting up and flood potential is increasing. I leave you to read the report to get the rest of the potential impact on erosion and fish resources in the watercourse as a function of a dynamic geomorphic area, the upper reaches of which are characterized by many natural landslides that continue to feed large quantities of sediment to the river.

WASHINGTON
Two papers from a journal Washington Geology (vol 26, no2/3, September 1998). The first is Flood Plains, Salmon Habitat, and Gravel Mining by Norman et al. The second (which is in the same e-file on the web) is Reclamation of Flood-Plain Sand and Gravel Pits as Off-Channel Salmon Habitat by Norman. These two very detailed papers provide a wealth of information on the topics noted in the paper titles. Well worth taking a look at if you are interested in geomorphology in general, gravel mining near rivers, and the spawning of fish in areas of such mining.

AUSTRALIA: NEW SOUTH WALES
Review of the McArthur Mine Open Cut Project Public Environmental Report prepared by Professor Wayne D. Erskine of the University of Newcastle, New South Wales, Australia is worth accessing if only to take a look at the pictures of the mine and the area of the mine. Seems as though the professor took issue with the adequacy of the original environmental report, particularly as it addressed proposed river and channel diversion works around the mine's open pit. The details of the controversy are not particularly important, and in the report, the professor notes that the deficiencies have been addressed. I paraphrase his recommendation/conclusions to give you some idea of what you may have to do if you proposed to divert a river around your mine:

  • Include artificial rock riffles in the diversion channels.
  • Incorporate large wood loadings, spacing, orientations and accumulations in the diversion channel design that mimic the current channel.
  • Provide detailed revegetation proposals.
  • Discuss meaningful the sediment erodablity for the material used to form the banks of the diversion channel.
  • Provide a stable diversion channel design and be prepared to do annual monitoring until vegetation is fully established.

PAKISTAN
A paper on the impact of mining in Pakistan is a welcome change from the normal. It appears that quarry operations to supply Islamabad are affecting the aesthetics of a range of hills. In a paper worth downloading and reading if only for the shear originality thereof I recommend The Effect of Mining on Geomorphology (Detection of changes by using remote sensing techniques)by Nawaz, Hamidullah, and Fayaz.

I quote and edit slightly: "For the last 30 years, since the capital city (Islamabad) came into being, the Margalla Hills have supplied limestone for construction of buildings, roads, and bridges. Geologically, the rocks in the area range from Jurassic to Paleocene and are of sedimentary origin, mainly sandstone and shale. That is the reason that the beautiful and green Margalla hills are being eaten up by limestone mining and crushing which in addition to destruction of the natural landscape is causing large scale environmental degradation and air pollution. The available aerial photographs show the situation before mining, during the mid of mining, and now the latest situation. Visual and digital interpretation of the available images together with GIS techniques will lead us to conclude and recommend certain concrete steps to stop mining and proposed certain other sites for mining."

PERSONAL OBSERVATIONS

Some personal observations to end this posting. Here are brief descriptions of the geomorphology of the states I passed through on a road trip from Iowa to British Columbia.

  • Iowa. This is a young landscape. A mere 14,000 years ago the last glacier receded leaving behind a rolling landscape of random rises and depressions and a crazy network of stream leading to the rivers that cut the state and flow to the southwest. On either side of the state are the great rivers that formed on the edges of the glaciers: the Missouri on the west and the Mississippi on the east. The glaciers left behind those deep clayey soils that make farming so productive.
  • Nebraska. This is a very old landscape. For hundreds of thousands of years the streams and rivers have flattened the state so that now one travels 450 miles from the Missouri to the western border along the Platte River that slowly meanders along a flat broad flood plain. During the periods of glaciation while Iowa was under ice, the wind blew silt from the eroding Rockies across Nebraska depositing those soils that now need irrigation to produce a crop.


  • Wyoming. Now we rise up the landscape that reflects the mountain building that has pushed up the Rockies and this state for the last 65 million years. The landscape is rugged: buttes and mesas, mountains and deep valleys that expose the old sediments that were laid down in the age of the dinosaurs when this part of the world was probably near the equator, the temperature was hot, and vast floods moved huge quantities of clay and silt and sand into shallow mudflats and lakes and swamps. Now these sediments are uplifted to 8,700 feet, the highest point along I80 and the Continental Divide at 7,000 feet.
  • Utah. I traversed only the eastern edge, coming down through the Wasatch Mountains that form the western edge of the Rockies and fall thousands of feet to the Bonneville Flats that once was an extensive inland sea, and is now a shrunken salt lake. Besides which sit Salt Lake City and the origin of this review.
  • Idaho. I traversed the flat part of southern Idaho. I avoided the mountains to the north. The flat lands where I travelled are that way because of vast outpourings of lava that came up as the continent moved west over the spot that now is Yellowstone and the volcano pipe that underlies the park.


  • Oregon: Hence across the big mountain ranges covered in deep snow and crossed by I84 also covered in snow and sand. Everything is pure white snow in sparkling sun. But you do go up and down great passes and deep valleys until finally you reach the Columbia Gorge that takes you down to the Pacific Ocean. What floods must have swept down this gorge to cut the wide and deep valley in which the river flows. I recall in some trepidation the Missoula Floods that resulted when the ice dams broke and swept across the landscape to create geomorphology that still dominates today.
  • Washington: Up I5 to British Columbia through those foothills of the Cascades and the views of volcanoes. Why would anybody go to Hawaii when the volcano created landscape is here so dramatic?

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