This document describes different types of waste piles, dumps, and heap leach pads. It discusses valley-fill, cross-valley, sidehill, ridge, and diked embankment configurations. Leach dumps or heaps are stacked on impermeable liners to be irrigated with leaching solutions. Dumps are generally placed on natural surfaces to promote drainage. The document outlines factors to consider for dump sequencing such as haulroad configuration and foundation conditions.

1. TYPES OF WASTE PILES, DUMPS, AND HEAPS
This section provides a description of waste piles, waste dumps, and heap leach pads (both lined
and unlined). Although these types of facilities are similar, the liner aspect introduces an
additional potential for failure along the liner as part of design. On the other hand, for unlined
facilities it is important to consider the materials’ geochemistry (both the ore as well as the
resulting pregnant solutions) and the site’s hydrology to ensure that natural water resources are
adequately protected.
Configurations
Collectively, waste pile, dump, stockpile, or a leach heap can be referred to as waste structures.
As such, their layout generally falls into the following categories, depending on the type of
waste, the purpose of the waste structure, and the physical constraints at the site. Each of the
configurations is shown in Figure 8.11‑1 and discussed in further detail in the following
paragraphs.
A valley-fill waste structure, as the name indicates, fills a valley. Many of the lined valley-fill
leach pads require some type of stability berm at their toes. Construction of a lined valleyfill
leach pad would begin at the toe berm and progress up the valley. Construction of a waste dump
(not a leach pad) usually begins at the upstream end of the valley, and dumping proceeds along

2. the downstream face (as shown in Figure 8.11‑1). For a heap leach facility, stacking should
begin at the toe and proceed up the valley to avoid slope-stability problems.
The top surface is usually sloped to prevent water ponding. Stormwater run-on can be controlled
by constructing diversion channels up-gradient of the facility. In steep terrain, where the facility
is going to take a long time to fill, it may be more economic to construct a rock drain below the
facility to pass stormwater. Subdrains may also be needed below the structure to control seepage
from natural springs and material drainage.
A cross-valley structure crosses the valley, but the valley is not completely filled up-gradient.
The structure is usually designed with a rock drain at the bottom of the valley to control the
storage and/or discharge of stormwater flows, or a water diversion system must be installed up-
gradient to provide drainage around it. This type of structure could also be used as a retention
dam for fine coal or waste slurries, in which case the design must conform to applicable
regulations for dams and impoundments.
A sidehill structure lies along the side of a slope but does not cross the valley bottom. This
structure may be constructed to impound either water or mine waste slurries (and therefore
would need to conform to applicable dam regulations). As with a cross-valley structure, a
sidehill embankment should also be designed and constructed with either stormwater diversion
channels or rock drains to control the storage and/ or discharge of flood flows. In some cases,
the hillside may require benching and/or a keyway at the toe to increase the stability of the
facility.
A ridge embankment straddles the crest of a ridge, and waste material is placed along both
sides. Unlike the crossvalley or sidehill configurations, this type of structure is typically not
used to impound fine-grained material or water. In some cases, one or both sides of the ridge
may require benching and/or a keyway at the toe to increase stability.
A diked embankment is constructed on nearly level terrain and can either impound fine-grained
or coarse-grained mine waste. By definition, this type of embankment is composed of two parts:
a down-gradient containment dike and the embankment or dump itself. These two parts may or
may not be isolated from one another by liners. If fine wastes are impounded by coarser waste,
the structure is considered a dike. If the embankment is homogeneous and coarse, the
embankment is termed a heap, such as a heap leach pad.
Leach Dumps or Heaps
Leach heaps consist of low-grade ores spread or stacked on large platforms where the pile is
irrigated with leaching solution to leach out the recoverable product of value. Although heap
leaching has been used mostly for precious metal and copper ores in the past, it is now also
being used for other products, such as uranium and nickel. In recent times, even municipal
wastes have been leached using similar methods to accelerate the decomposition of waste and
add capacity to the facility. Heaps are normally placed on impermeable liners of natural and
synthetic materials (discussed in more detail later in this chapter).
Dumps usually refer to material piles created by end dumping. Run-of-mine ore is sometimes
simply dumped instead of being stacked on a leach pad and leached for economic recovery of
the contained commodity (a process known as dump leaching). The same procedure is often
used for secondary recovery from leached ores. Dumps are generally placed on natural soil or

3. rock subgrade surfaces that have been demonstrated to have some degree of natural solution
containment and are normally located on sloping ground or in a valley to promote drainage to
the toe.
11.1 Dump and stockpile management plan
Construction of the waste dump or stockpile is generally the responsibility of the mine’s
operations department and involves several activities:
 Transport of waste and stockpile materials from the mine or mill to the dump or
stockpile
 Placement of the materials in the dump or stockpile in accordance with the planned
development and operating plans, including lift height and location
 Access road construction and maintenance
 Clearing of new areas for dumping or stockpile construction, foundation preparation
and drain construction as required
 Maintenance, upgrade and expansion of surface water management facilities
 Environmental monitoring of conditions at the dump or stockpile, including seepage
water, surface water and groundwater quantity and quality
 Dump and stockpile performance monitoring and documentation, including stability,
erosion, consolidation and creep.
Environmental monitoring is normally the responsibility of the mine environmental group and
may include surface water, sediment, seepage water, groundwater levels and quality, dust and
air quality, and geochemistry sampling
11.6.9 Dumping sequence
The dumping sequence should consider the following factors:
 Haulroad configuration – typically, dumping will commence as close as possible to
the open pit; however, some dumps may require that materials be placed preferentially
in particular areas to achieve adequate stability in subsequent lifts. In this case,
additional haulroads may be required to facilitate access to different dump areas at the
same time.
 Foundation conditions – where steeper foundation slopes occur, it is often preferable
to advance the dump along the contours rather than down the slope. Where lower
strength materials exist in the foundation, the designer would identify whether the
materials must be removed or can remain in the foundation. In cases where they can
remain without causing instability, it is often necessary to sequence the dump
development to confine such materials and avoid local interim stability issues.